I thought he sounded odd at first, too. However, I watched it again and don't feel that way. Mainly because I realized I was imagining he'd have Japanese Sora's voice. But once I remembered how Haley voiced lines like, "That's tough talk from someone who stood on the sidelines and let his Nobody flunkies do all the fighting," I realized he was still delivering the lines the same way. That line reminds me of this one in the new trailer, "At least I know who to blame!" For the most part, I think Haley's doing a great job. It must be difficult to sound so young all the time...
But this is all just my opinion ^_^