Hm..well, yeah. Tobi seems to be intelligent. Quite intelligent. BUTThe real problem with Tobi being Obito isn't in his looks, but in his mind. Tobi seems like a mastermind, he seems even quite intelligent, while Obito's intelligence stat from the Databook was 1... his current state of mind, motivation, the reason for performing "THAT" plan are, understandable, but the big jump in intelligence seems quite strange.
Still, he might not be Obito, because in reality, most Shinobi would have their wish unfulfilled, their promises shattered and their hopes pulverized.
If he is obito and he really worked with Madara and Zetsu and was trained by him, then it would be reasonable for him to improve his strategic abilities. Even naruto, that was a total dumbass is the pre time skip was able to pull out some good strategies and over the 2 years he improved even more. I think the problem with Obito was that he was a lazy boy who didn't take reality too seriously, until everything he had and everything he believed in crumbled. Suddenly he had a motivation, given to him by madara and he got over his lazyness. If he started training seriuslu under the biggest mastermind in history, then he himself would become quite good at it.
There is still the possibility that Tobi (if he's Obito) is just following Madara's instructions. Like Madara made all the plans and was the mastermind behind all this and Obito has all ready. He just has to follow the path madara traced for him. And he still has zetsu for consultance, in case he would do something stupid.
I see only 2 possibilities: tobi is either Obito or Izuna, afterall the guy entrusted his eyes to madara who failed at protecting his clan from senju, but i don't see how would izuna behave in such a ridicolous way he did in the deidara arc. I just don't see a serious uchiha making a fool of himself. Obito on the other hand was clumsy from the start, so he may accept the role of a clown way easier than a serious character. (just remember how vegeta didn't want to use fusion cuz it was ridicolous. A real serious villain wouldn't behave like that. He would rather die XD)