Jaleel Whie or Death!
Ok not really but it's been a decade so it's about that time it seems. It's like every decade they switch up the voice.
Also Sega seems to want Sonic's voice to be consitant across all mediums, as the game's cast usually end up doing the cartoons as well. So, its not surprising to me if they Switched from Roger to Ben That way those that might have gotten into Sonic with the movie (I know a few) if they play a new game its the "same" Sonic.