Good chapter, it wasn't excellent because too many pages were wasted with flashbacks, 1 or 2 pages would be enough i think.
Yes, it truly is Obito and, like it was expected, he seems to be doing this because of losing Rin since he died for her and Kakashi and entrusted her safety to him. She was the trigger to his passage to the dark side. And no, this is not lame. It's actually well written and thought. Just a question remains, how did she die? Not that it is really that important.
And now Madara shows up...two things must be said, he knows Obito thus it's the confirmation that he was the one behind his salvation and transformation just as expected and secondly, how the hell is the Naruto team gonna deal with this duo? Unless a miracle occurs, they are gonna lose. But i think the Kages and the united army are arriving so maybe something will happen. I just hope Madara, with his ego, will explain this whole Madara-Tobi-Nagato-Obito story before tearing everyone down.