It's not Obito. At least, not completely. There are dozens of reasons why it wouldn't be, and why it wouldn't even make sense. Obito died to save Kakashi and Rin, and Obito's last action was to give one of his new sharingan eyes to Kakashi. Yet, despite this very close connection, Tobi hasn't even once acted as if Kakashi was somebody close or familiar. At least, no more familiar than any other ninja with the same fame and name recognition.i believe its obito
Tobi, as a grown man with significant power, fought Minato when Kakashi and (if he were still alive) Obito were still young.
As Madara Uchiha, or somebody pretending to be Madara, Tobi either participated in the Uchiha massacre or at least supported it. He also has a significant grudge of some sort against the ninja world in general but hasn't expressed any particular grudge against Konoha in particular. Why would Obito, who died protecting his friends and believing that friendship and helping teammates was the most important thing for a ninja to do, try to enslave the entire world and sacrifice his Akatsuki team members (not to mention his fellow Konoha ninja brethren and Uchiha clan members) to pursue his goals? That's exactly the opposite of what Obito would do.
And, keep in mind that Itachi was secretly a good guy with peaceful ideals, but he pretended to be a bad guy in order to protect the village from Tobi. Tobi cannot be pretending because HE'S IN CHARGE. If Tobi didn't want the village or his old friends to get hurt, he wouldn't have started this war in the first place.
Tl;Dr: It's not Obito. It can't be and it wouldn't make any sense if it was. Obito died. His only legacy in the entire manga was to give his eye to Kakashi. There is no more Obito!