I personally absolutely hate this for a pre-existing universe with characters that I already care about. I don't give a crap about being in the story, or expressing myself in the game. Forces custom characters should be a part of a separate title that doesn't use Sonic, Tails, Eggman or anyone else we already know. They could still tell the story of a world where Eggman's forces have won, but a long time has passed since then and Sonic and Co have all disappeared from the world/it's an alternate universe, so a rag-tag team no unremarkable heroes, aka "the Sonic Forces", must band together to save the world. Why does Sonic need my help? And how the hell am I going to impact the story and work as a character? I just don't think that it's at all right. If the series continued down this track without also going the more traditional route too I'd be seriously disappointed.