Sumo Digital was asked about voice chat in Sonic and All-Stars Transformed after the Wii U voice chat news came out. Here's what Sumo Digital had to say.

We don't support voice chat on WiiU for those reasons, one of the side effects of being a launch title basically.

Maybe if the game gets another sequel, we can hope for some online chat. Not this time around, I'm afraid. Thanks to Autosaver for the heads up!