Everyone post SA1 went with the best design for sure. Blaze is the only one with some alternates that could be ok besides the actual look she has now. Those Shadow, Big, and Cream prototypes are straight garbage and disrespectful lol.
And on the sixth day the LORD David Bowie created man and woman in His image. And he saw that it was good. On the seventh day the LORD created videogames so that He might take the bloody day off for once.
Since I'm traveling down memory lane, this is the post I touched upon that explains the tumultuous history behind SA2. (TL;DR - blame the fans)
The problem was that Sonic Team refused to confirm whether or not Tails was in the game, and apparently there was enough people out there who pestered Sonic Team at conventions and such about Tails not being in the game that Sonic Team announced they would be going back and putting in more "friendly faces" in the game, notably Tails. While not directly confirmed, there are suggestions that this signaled a pretty significant change in the whole entire design of Sonic Adventure 2.[...]
[...]Tails and likely Amy Rose were shoe-horned in (think about it: Amy contributes almost nothing to the story), and the overall plot was lightened up a little bit. But most importantly, the roster of playable characters went from 3 to 6, and the "team rivalry" system was born. Shadow was now playable, as was Rouge, to make up for the fact that Tails was now Dr. Eggman's rival.
It is somewhat likely that Shadow, Rouge and Tails were given levels that were intended for the branching path system. Whereas you would be presented with a choice that would either lead to LEVEL A or LEVEL B, now LEVEL A would be for Sonic and LEVEL B would be for Shadow. Unfortunately for Shadow, there probably weren't a lot of LEVEL B's to go around.