Yeah I don't know what they were going for with his English voice. It's like '06 Silver, but deeper. I don't hate it though, and am grateful it wasn't an "annoying child" or obnoxiously high pitched anime voice. His dialogue is what makes him hard to listen to. The voice itself is inoffensive.
I don't mind the anime kid voice in Japanese but I don't think it would have translated as well into English. I think this game has one of the better dubs in the series; even though I only replay Sonic games in Japanese, I liked Griffith's performance here better to Shadow and 2006.