For 1, getting past Obito's intangibility is by no means an easy feat. Naruto, Bee, Gai and Kakashi working together only managed to land 3 blows on the guy and that was only thanks to Kakashi's Kamui. Something Itachi doesn't have. Not to mention that it took Kakashi a while to deduce the abilities of Kamui, a prodigy himself. Regardless whether Itachi can figure out the weakness to Kamui does not equate to the fact that it's a tough ability to figure out, tough to fight against and Itachi does not have a great counter that Obito himself can't counter with Kamui. Sure it's one technique but the powerful thing about it is Obito's versatility and using the move. Incredible speed coupled with his reflexes to keep BM Naruto at bay and dodge Ei easily is proof that landing a blow is no easy feat, especially since Itachi isn't as fast as Naruto, Gai, Ei and arguably with Bee and Kakashi.
For 2, that's not the typical interpretation of that scan. When Itachi said only those with a Sharingan and be of Uchiha blood, that didn't mean only Sasuke, that meant for any Uchiha with a Sharingan and a MS only helps Obito's case. As for Izazami, Itachi has no idea on who the man behind the mask is. Pulling off Izanami on Obito is a wishful scenario in one case but Itachi wouldn't even know if such a genjutsu would be effective cause he has no idea about Obito like he did with Kabuto during his fight. Kabuto talks a lot while Tobi did not. He won't reveal of enough of his personality, ideals and such in a fight in this scenario.
I think Obito wins this mid-high diff but the arguments you used in this thread was flawed so if you wish to convince someone in the future, you may want to organize your thoughts better and back them up a bit more
