Disclaimer: Long and convoluted post, but please bear with me here for a bit.
What if in the Ressurection F arc neither Goku nor Freeza are really that ahead of everybody outside of their Blue/Golden forms?
We know in Battle of Gods Goku's base was weaker than Freeza, but after Whis' training he managed to get strong enough to defeat him as he was on Namek. In this case, his God power was lost after the battle with Beerus. He would be able to use God Ki, as it was still inside him, but only after achieving Blue.
Freeza's training on the other hand has all been about learning to master Ki control, so his forms aren't necessarily supressing his power anymore. This could make him about as strong as his Final Form even in his First Form, only gaining marginal power by transforming outside of his Golden form.
This would mean that Gohan got as weak as a Namek era Super Saiyan. In the movie, Freeza one-shots him in his base form, while in Super, even though Gohan is a Super Saiyan, Freeza cheap shots him while he is talking with Ginyu.
Piccolo is also not really shown to be fighting at full power, which we can take away from him not taking off his weighted clothes at all, otherwise this would be the only time in any series that Piccolo is using his full strength while clothed. This might be the reason he doesn't seem stronger than Gohan, in the arc at least.
So what we would have is:
F base Gohan ~ Namek Goku
F SSJ Gohan ~ Namek SSJ Goku
Piccolo Full Power ~ Cell Jr
Piccolo weighted ~ Namek Vegeta
F First Form Freeza ~ Namek 100% Freeza
F Final Form Freeza ~ Mecha Freeza
F base Goku ~ Yardrat SSJ Goku
This means that Goku's Super Saiyan form in the U6 arc and subsequent appearences is still as powerful as his Buu arc version, or the Full Power Super Saiyan, with his base being around as strong as a weak Super Saiyan or Android level opponent, but weaker than the mastered form.
Therfore, after regaining his strength in the recent episode, Gohan is finally back to matching his father in Super Saiyan, while being weaker in base, just like we see in that fight.
Even the statement about Shisami and Tagoma being around as strong as Zarbon and Dodoria works, with Shisami being nothing to base Gohan, while Tagoma who trained with Freeza reached the level of his Emperor's Final Form on Namek.
The stuff that doesn't work is this is assuming Piccolo could have taken on even Freeza's Final Form if he was serious, but it is possible he, like everybody else, knew he must be hiding something up his sleeve. Of course, in this case Piccolo should have just powered up a bit and trashed Tagoma, but he might have wanted to keep his power in case they had to take on Freeza himself (akin to his dumb plan to let Gero one shot him). And not just that, but instead of dying like an idiot he could have tanked Freeza's blast, but again, maybe everything happened too fast for him to do anything (kinda like how Gohan's arm got busted when he protected Cell).
I would explain that again by Freeza's training. He learned Ki control so he might have been able to use more power than usual in his Final Form or than what he showed Goku, but decided to go Golden since he knew his opponent was holding back his transformation too. In this case, while Freeza vs Goku was a battle held at a bit above the powers of their initial battle on Namek, neither was serious until transforming. They pretty much tested eachother to see how much they improved since then.
Then, the only other instance of the base forms being God level is in the Potafeu arc, when Copy-Vegeta was tanking SSJ3 Gotenks. This could be handwaved as stupid filler that Toriyama doesn't take into account when writing any of his stories. Or, as an explanation, the Water is unkillable anyway, without destroying the heart-shard-thing, so Gotenks wouldn't have been able to hurt Copy-Vegeta no matter how hard he tried. Goku wasn't doing any damage either and for a fact he is about equal to Vegeta at this point.
So in conclusion, everybody, outside of the God/Golden/Rage forms is pretty much at exactly the same levels as before, only that Goku, Vegeta and Freeza can raise their powers even further than before, but not enough that transforming isn't still a viable option.
Black is only as strong as SSJ3 in base because Zamasu was already SSJ2 level and he transfered his power to Goku's body and then got power ups from fighting Trunks.
Trunks is able to match kid Trunks' SSJ form in base because he learned to also raise his powers more than usual in his base form, as seen when he deflect Black's blasts in the first episode of the arc without transforming, but when going on the attack next episode, he does indeed transform.
I know this is twisting everything that happens in RoF to pretty absurd levels, but the story is absurdly written itself.
