I would love to see the 8th gate activated, but I don't think he will. At the current stage of the battle more speed and power wouldn't make a great difference. Even people who can teleport have trouble keeping up with Tobi, plus Naruto's already shown that he can flash in nine-tails mode.
I don't think this scene is going to culminate in battle. I think Naruto is going to convince Tobi that he's wrong. There hasn't been a villain yet that he hasn't been able to convert and now that they know Tobi is Obito there's a strong incentive to not defeat him.
Kakashi's never gotten over Obito's death, it's made him who he is. Even as much of a villain as Tobi has been I don't think they'll have the heart to kill him.
There's something wrong with Tobi as it is, if you notice he has great control of his MS in being able to phase his body with it, but he doesnt use any other EMS powers, even though he's planning to create Infinite Tsukyomi, we haven't seen him use regular Tsukiyomi or any other genjutsu, nor has he used any Rinnegan powers. The way he fights doesn't line up with how any other Uchiha fights, Tobi manpulates himself with his MS but every other known Uchiha manipulates their opponent via genjutsu. Someone with such a strong MS should be able to summon Susano'o. i hope Ch.600 explains some things
Can i just add, this is gonna be the longest week ever, in waiting for the new chapter!