Hmm, a most interesting start to your story and I look forward to seeing wherre you take it. An AU with a point of departure that early leaves room for all sorts of fun. If he takes the route indicated, I rather suspect he's going to change his third year elective choices and that should bring some enlightening disputes with Ron; what having him actually working hard to his fullest capabilties does to his relationship with Hermione will also be quite instructive of her true character. Heh, an industious and rapidly-learning Harry could also lead to some revelations if Dumbles has any manipulations going on that require an un-inquiring underachieving Harry.