So Obito's death lead to Konoha's attack?
Thanks to the most recent chapters, we've managed to connect a few more dots in this whole "tobi is ..." chain of theories. Now, instead of trying to find out who Tobi is, I will point out some obvious things that some of you might have missed. If this was made before, I couldn't find it with the search bar, so sorry in advance.
Anyway let's begin:
1. Tobi being a former shell of himself
This was stated by Itachi and Tobi himself. This makes me think that Tobi had MS/EMS in the past and lost it. In case he had MS, he overused it. Now he's trying to steal the best sharingan eyes and make due. Which is probably how he got Obito's. But wait it gets better... I believe Obito's death helped him with his plan more than the fox did, which I will get into right now.
2. Tobi being able to use Kamui for years and years
I'm guessing that Tobi is (a) either using Kamui very rarely (just when we saw him in the manga), (b) or that borrowed eyes doesn't strain you so much (look at kakashi) (c) or that he actually obtained EMS by taking Obito's remaining eye, meaning that he must be related to Obito is one way or another. One thing's for sure, he's got the same Kamui that Kakashi has, only it's a level above in terms of skills.
3. Tobi waited for an opportunity to attack Konoha
So I think Tobi waited a huge period of time to find the right moment to attack. And manga pretty much insinuated that the only reason Tobi attacked, was because Kushina was giving birth. I think that's only half the reason. Tobi obtained some power. He probably was looking for sharingan after sharingan to find a powerful one to replace his, and when he finally discovered Obito's, it was only a matter of time until he unlocked his true potential and could finally have enough power to attack. I think controlling the fox was secondary, due to the fact that his MS/EMS wasn't enough anymore to do much damage. Tobi was stuck with S/T + izanagi in case of emergency and that was all.
In conclusion, can we say who Tobi is? No, not really. Not with 100% certainty. But knowing that he was a former shell of himself and obtaining MS/EMS very fast after Obito's just awakened his sharingan can be some important clues as to who he is and this might very well explain his actions.