95% of anime isn't drawn by the man who invented SSJ though, is it? And the heroes of anime may often have spiky hair but the key thing here is that the hero's hair goes spiky after he powers up and become super powered.
It's not like DBZ is the only series where hair goes spikey after a transformation.
Anyway, it's not just spiky hair for the hero. He gets the same eyes as a SSJ and the change is particularly highlighted because he normally has the same eyes as non-SSJ Goku or Gohan.
And those eyes are to show... what again? Oh, that's right, anger.
The aura may be a different colour but it's still a glowing aura, the exact same eyes as a SSJ and spiky hair and all brought on by powering up and reaching a state of "high tension".
And almost everyone in Z has glowing auras. Lots of non Saiya-jins have eyes like those (it's part of his art style for crying out loud). And there had to be some sort of change for the High Tension state or it'd be rather bland of a power boost.
IIRC Angelo's hair also lifts up in a way similar to Trunks' when he goes SSJ.
You really need to play the game again. I'll repeat my earlier statement. The Hero is the
only one that gets a physical change. Everyone else just gets the glowy light and angry expression.
Toriyama obviously wasn't going to make it identical to SSJ because that would just "break the fourth wall" and detract from the DQ setting but he made it as close as possible without it being a direct copy so it remained a nod to fans rather than making Dragon Quest Z instead.
Toriyama's got a unique and distinctive style. It's easy to pick up similarites between designs of his. And beyond that, hell, I wouldn't doubt he didn't even remember what a Super Saiya-jin even
looked like when he was working on the designs of DQ8.
As for Jessica's eyes - they're not merely squinty like they are when she's injured.
I didn't say they were
exactly the same. I said they weren't that much different.
They're the exact same as SSJ eyes and when you consider this is the same artist that did the SSJ eyes it doesn't take a genius to figure out the link.
Again, we're talking Toriyama here. He uses that eye design a lot to show anger/evil. What
else would you expect him to use for a High Tension expression? There's only a link if you read into it too much looking for what isn't there.
I repeat again; you make your character power up several times in a row, they reach a special state after a while, become much more powerful and change their appearance to one very similar to a SSJ - and the designer was Akira Toriyama. Oh but it's a purple aura rather than a yellow one and Jessica's ponytails don't burst out and change into Goku-esque spiky hair. Silly me, it's totally different.
It is totally different. You're only seeing similarities because you
want to see them. Not
every spikey haired transformation, even when drawn by Toriyama, has a connection to Super Saiya-jin. We're talking about an artist that uses similar designs
constantly. Angelo looks like Trunks. Kalderasha and the guy at the Monster Arena look like skinny versions of Hercule. There's female soldiers around that are basicly wearing pink versions of Chi-Chi's metal bikini. There's other characters who look like characters from other Toriyama works. There's no relation beyond the fact they were drawn by the same person.
Toriyama said he didn't know how a female SSJ would look. Well what could he possibly have meant? If he was referring to their often longer hair. what about SSJ3? i.e. he already drew a SSJ with long hair. If he meant the eyes then why wouldn't they have the same evil eyes as a male SSJ? The eyes he gave Jessica and not entirely dissimilar to #18's eyes. There really isn't anything that he would have been confused over; there's nothing that would be different for a female going SSJ. The Jessica thing is just the icing on the cake really.
Ummm, how about the
huge freaking muscles and bulk they gain when they transform? Super Saiya-jin makes their musscles bigger and more defined. It's a
very 'masculine' transformation. And hell, a female wouldn't even nesacarily have golden hair and teal eyes. You're just generalizing and, again, grasping at a non existant point.
They'd be all "imma supa saiyjin!" and Chichi'd be all "whatever, bitch". Then she'd punch their tits out their backs. 
