Remember, the guy who does Sonic's voice just did a turn as Batman.
Hey, the guy who just did Batman's voice will be doing Sonic next. A new behind-the-scenes video for Sonic Boom looks at how Sega's signature character will be changing in his new video game and TV show. A few quick glimpses of the Sonic Boom game get shown and developers working on it talk it up as an action-adventure game with an emphasis on story and teamwork. And, yeah, the guy behind the mic for Sonic is the same Roger Craig Smith who voiced the Dark Knight in Batman: Arkham Origins.
Edit: As folks have noted, Smith has been voicing Sonic for years now so the first sentence has been changed to reflect that fact.