If you could change anything in the whole series what would it be?

[kinisking]

Nah the arc was supposed to be Gohan realizing his hidden potential. That was built up throughout the manga. Also Vegeta isn't meant to surpass Goku. I don't see why you think the time travel is so interesting. It really didn't do much for the story. It could of easily progressed without time travel. All the time travel did was create confusion.
Also like I said, androids being stronger than Frieza makes no sense, and Vegeta should be the one to finish off Frieza, and Vegeta going ssj for the first time to finally beat Frieza makes sense.

It sounds like a big change but it really isn't. It's the same arc, but with no future Trunks (who did nothing anyways besides kill Frieza and that wasn't even needed or a main part of the arc). Also I think bring back Frieza as a threat for Vegeta to go ssj against makes for a more interesting story than Frieza coming back to be a jobber.
Also I think already having the threat of the androids and not knowing how to win, and then adding Frieza on top of that would increase the suspense. Of course Frieza wouldn't last long and he would really only come for Vegeta to attain ssj, and for Cell to get his DNA.
If you really hate the idea of Frieza coming back later and being a threat you could always have him come back and be killed by Goku like in the original timeline and just leave out time travel, but I thought Frieza coming back while the androids were around would be cooler (no pun intended).

Gohan didn't even interact with cell until the last fight. Their was no emotional build up to their confrontation or past relationships to work with. It was random.

Vegeta was an asshole the entire arc leading up to the payoff of cell killing trunks. He was one of the only people in that arc to get character development and he should have been the one to redeem himself, turn SSJ2 and kill cell after neglecting his son and letting cell transform.

Gohan's build up and hidden potential was forced since he regressed as a character from the frieza arc, was thrown into a fight he had no right being in and was having multiple personality disorders throughout it. In the end he needed daddy to hold his hand.

Frieza's presence and death had one job and that was to set up the Androids as a bigger threat. He's irrelevant to this arc.

The time travel element was used to represent a future where the Z fighter failed and an assassin and ally sent from the future to alter the past. Terminator homage which Akira Toriyama is a big fan of.

I'm not of huge fan of the cell arc because it was pretty boring but your idea (no offence) is dreadful.

Unless you didn't pay attention to other characters or nostalgia, the time travel element is pretty important

Trunks was great as well.

Why do people always bring up the fact that Gohan didn't interact with Cell until the final fight? Isn't that Goku against Vegeta? Isn't that Goku against Freeza? Don't bring up the saiyan race because we all know Goku didn't give a shit about them. He fought Freeza because he was messing with his friends. Same with Gohan.

[Almighty Majin]

Part 1 Dragon Ball will stay the same except for a few things:
Pilaf stays as a consistent rival (he can still be silly and comedic, but also be a threat using various machines kinda like a funnier Dr. Robotnik)
Give Monster Carrot a legitimate defeat
Upa gets trained by Roshi and also becomes a Z Fighter
Yamcha should have fought and defeated Tambourine while Tien defeats Drum
King Piccolo does not kill Shenron (that scene pisses me off because it makes Shenron look so weak and makes no sense either since Kami > King Piccolo)

Part 2: I'm changing up the sequence of events here
1st arc - Dr. Gero's Revenge Arc (Androids 19 & 20 wreak havoc and must be fought off by the Z fighters, maybe throw in Mercenary Tao one last time for closure)
2nd Arc - Raditz Saga (Raditz lands on Earth revealing to be Goku's brother and then the same events ensue)
3rd Arc - Androids (Goku is dead and Androids 16-18 appear during the year of training for the Saiyans, Android 8 could also return as an ally here and get upgraded, Goku's training could involve Raditz) (Training for Goku leads to character development for Raditz similarly to Piccolo's development and Yajirobe breaks his laziness)
[the Androids won't get killed as they weren't inherently evil to begin with, but they must be defeated anyways]
4th Arc - Saiyans (Nappa and Vegeta arrive and events go as normal, the Androids join the fight against the Saiyans)
5th Arc - Namek (Piccolo, Tien, Yamcha, Chiaotzu, and Android 17 are dead and must be revived, only Zarbon, Dodoria, and Cui are here, Vegeta uses his tail to transform against monster Zarbon)
[Krillin, Gohan, and 18 attempt to take the dragon balls and are left to deal with Vegeta until the Ginyu Force arrives, King Kai trains the humans, Piccolo, 17, and Raditz (change of heart) and teaches them Kaioken]
6th Arc - Ginyu (Goku is recovered and goes to train under 100x gravity while Android 16 was repaired and upgraded to train with Goku as well, Vegeta gets his tail cut off from Krillin and the Ginyu Force beats up everyone of course, Nail intervenes to help out, Goku vs Ginyu happens and then everything goes as normally planned in series)
7th Arc - Freeza (Freeza eventually comes to deal with this mess while Goku recovers and Android 16 being tended to by Bulma, Vegeta grows his tail back, battle with Freeza is normal and then Piccolo vs Freeza happens, Piccolo has fused with Nail and uses Kaioken to fight third form Freeza and even final form for a little bit, Vegeta gets last Zenkai and then uses ape form for a good fight, but loses and dies anyways, rest is normal)
8th Arc - Yardrat (Goku's training on Yardrat is shown, dead people come back to life, Turles is made canon and appears in Goku's absence as a villain)
[DBZ Sagas is a horrible game, but showing Goku's training on Yardrat was pretty cool so having him fight a strong warrior like that would be cool]
9th Arc - Cell (Future Trunks comes from the Future to warn everyone about Cell who takes everything over via army of bio androids and becoming perfect, 3 years of training happens, Imperfect Cell makes quick work of SSJ Vegeta, Cell games happens normally, but Cell Jr.'s have character similarly to King Piccolo's children)
[after Trunks dies, Vegeta should explode to SSJ2 and fight Cell and should end with Gohan and Vegeta finishing him off, Goku and Android 17 are both in otherworld after Cell blows up]
10th Arc - Freeza's Revenge (During the 7 years, Mecha Freeza lands on Earth with King Cold, Cooler becomes canon as well, Goku and 17 are training in otherworld and achieves SSJ2 and the filler tournament becomes canon)
[Some more training would be shown as well such as Tien and Chiaotzu, Krillin and 18, Yamcha and Yajirobe, Vegeta, 16, and Trunks, Piccolo, Gohan, and Goten]
11th Arc - Babidi (Spopovich and Yamu are fought by the human Z-fighters, Pui Pui and Yakon are made to be more impressive than canonically, make Dabura a force to really be reckoned with, Majin Vegeta + Majin Piccolo)
12th Arc - Buu (everything goes the same here with maybe some more feats from Supreme Kai)

Super:
BoG - Vegeta goes SSJ3 when Beerus slaps Bulma, no 10% line, introduction of Champa and Vados like in the manga
FnF - The training and god ki are explained thoroughly, Champa and Vados interact with Freeza's Army after passing their ship, they train Freeza post revival in order to explain power increase, Tagoma and Shisami also train, Piccolo fights Shisami and Gohan fights Tagoma and they win, no Ginyu return, everything else is normal except Vegeta kills Freeza instead and no time rewind.
U6 - U7 Team will be Goku, Vegeta, Gohan, Piccolo, and Buu, Whis trains the last 3, Vados trains U6 team sans Hit, Frost isn't evil
Interlude - Goten and Trunks train, Goku SSJB Kaioken vs Beerus
Black - Give Future Trunks SSJ3, give more context to F. Trunks' power (throw in more training scenes), Fusion Zamasu should easily beat everyone, Vegito should be the only challenge for him and then should play around a little too much a la SSJ4 Gogeta, Future Trunks was taught Mafuba by Piccolo when Goku was learning and Goku should have taught him the Genki Dama as well, Ethereal Zamasu still happens and is destroyed by Zen-o, his timeline is revived via super dragon balls

[dragon boss z]

Cell had the androids and Trunks as arch enemies. Then eventually Gohan...

Also Goku didn't have anything personal against Freeza till when they actually fought.

The androids were pretty much Trunk's arch enemy, not Cell himself. And Frieza killed Goku's dad, mom, and the rest of his race, lol. His men were also trying to kill his friends and his son for like a month, and then Frieza himself was torturing his son while Goku was trying to recover from his injuries. He also almost killed Krillin before Goku got there, and he then killed Vegeta right in front of him. Then mid fight Frieza murdered his best Friend.

Cell killed 16 in front of Gohan, but Gohan barely new 16. He later killed Trunks who was wished back like right after. I would say the biggest thing Cell did was kill Goku. All in all I would say Gohan was the right person to kill Cell.

[DBZAOTA482]

Cell had the androids and Trunks as arch enemies. Then eventually Gohan...

Also Goku didn't have anything personal against Freeza till when they actually fought.

The androids were pretty much Trunk's arch enemy, not Cell himself. And Frieza killed Goku's dad, mom, and the rest of his race, lol. His men were also trying to kill his friends and his son for like a month, and then Frieza himself was torturing his son while Goku was trying to recover from his injuries. He also almost killed Krillin before Goku got there, and he then killed Vegeta right in front of him. Then mid fight Frieza murdered his best Friend.

Cell killed 16 in front of Gohan, but Gohan barely new 16. He later killed Trunks who was wished back like right after. I would say the biggest thing Cell did was kill Goku. All in all I would say Gohan was the right person to kill Cell.

Trunks hated Cell just the same as the Cell... probably even moreso.

Cell also tortured Gohan both physically and mentally just so he can challenge him... even going as far as to seek his children at his friends. He's pretty much to Gohan what Freeza is to Goku (an unrepentantly evil being who managed to push the pure-hearted warrior to his limits).

[dragon boss z]

Trunks hated Cell just the same as the Cell... probably even moreso.

Why do you say that? Androids 17 and 18 are the ones that killed everyone he loves.

Cell also tortured Gohan both physically and mentally just so he can challenge him... even going as far as to seek his children at his friends. He's pretty much to Gohan what Freeza is to Goku (an unrepentantly evil being who managed to push the pure-hearted warrior to his limits).

Ya, that's why I said Gohan was the right person to kill Cell. The other guy said Vegeta should of and I disagreed.

[RedShift]

• Install some really f***ing big breaks on the power scaling. I'm fine with growth but holy cow some of it is just stupid.
  
  Eliminate Future Trunks completely. Goku gets the heart Virus and is put out if commission while the rest of the cast has to deal with the Androids. Vegeta attains super Saiyan this way, Piccolo Fuses with Kami to hold the line. The rest of the arc goes on as normal from the point of Piccolo vs 17.
  
  In Goku's absence, Gohan continues training with Piccolo & Vegeta. All three progress.
  
  Fat Buu was never a thing. Super Buu is released from the Egg instead and immediately absorbs Dabura...I'd really just re-write most of the Majin Buu & Fusion Arcs.

[Esfír Dedragón]

Oh, there are just SO MANY things I would change. Others here have listed some of them that I concur with.

But if I could name just a few that have bugged me for years, it would be the following:

1) Make the Red Ribbon Army saga contain some kind of foreshadowing of the inevitability of the Androids. Like, have some kind of early reference (visually or verbally) to Dr. Gero. An example that I could think of is that Ninja Murasaki should have told No. 8 that "Your creator, the Good Doctor, said you had obedience problems when creating you among all the others..." or something like that.

2) Give a better, detailed explanation as to how the Pilaf gang found the jar that contained the Great Demon-King Piccolo. Maybe they found it on accident? Or tried to prove/disprove a legend? And make them permanently dead after they fall from the sky.

3) Re-write the scene of how Piccolo (jr.) was born. I personally like the idea of Demon-King Piccolo's head being the only thing that survived the explosion and being the "egg" that housed a reincarnated version of him. Sort of like a cocoon containing a butterfly.

4) Explain and show how the original timeline came about; from the arrival of Frieza to Trunks fighting the Androids one last time before going to the past. Oh, and address whether or not Future Android 16 and Future Android 19 were ever created.

5) Perhaps go into the other timelines or simplify them.

6) Give GT another try and properly execute their story arcs.

7) Given that I view Super and it's related content as an "Enjoyable Failure", it's a bit too soon and somewhat pointless to discuss what can be changed. Perhaps when it ends, I can finally say it.

[Zeru14]

Launch, 17, Tarble and Tights making more guest appearances.

Great Namek vs Great Ape

Yamcha learning Kaioken from King Kai in the Frieza Saga and teaching Krillin. Fat Buu watches one of them during it and learns by his copy skill ability.

Yamcha finding love with Tights, Bulma would of course be uncomfortable with her ex and sister dating, but after seeing them be happy come to support the relationship.

Tien unlocking special abilities with his third-eye similar to Despero from DC Comics.

Chiaotzu gaining Jean Grey level psychic abilities.

Gohan learning Spirit Bomb from Goku.

Vegeta training hard after the Kid Buu battle and unlocking SSJ3.

Satan wearing a jet pack like in the videogames.

Bulma builds Gravity Rooms for Gohan, Yamcha, Tien/Chiaotzu and Krillin on their respective properties so they have an effective training method close by.

Kid Trunks, Goten and Marron have older appearances. Kid Trunks would be as tall Future Trunks was at the time of Future Gohans death, Goten will be at a similar height and starting to grow his hair out and Marron would be starting to resemble her EoZ look.

Bulla being born by now.

Piccolo gaining access to the red-eyed form putting on par with Super Saiyan Red.

Forgot one, Future Trunks with purple hair in the Super anime, so him and Kid Trunks who are the same person genetically, will freaking match.

[Smilodon]

The U7 gods would be Vados and Champa. I don't like Whis and I think Champa is more funny than Beerus!

[FoolsGil]

I'd also remove zenkais.

[Neo-Makaiōshin]

I'd also remove zenkais.

And by extension battle powers.

[GodKaio-Ken]

I would have waited longer before Cell blew himself up and had that be the ending. Goku giving his life for Gohan who went all out but couldnt finish the deal would have been amazingly meaningful.