The power stone in this chain of tournaments lets the wielder get the first hit in a match. So assuming the player doesn't drop the combo they might be able to make it 2v1 in that match.
I don't think the tournament Power Stone is going to lead to too many ToDs. You only have one bar to work with and once your opponent has 2, they are going to break out with Counter Switch. Have there even been any ToD combos discovered that can be done with one bar starting out and no Stone meter? Still, first hit and positional advantage can't be underestimated.
Well we are only a month into the game's life with three new characters just released. We will see if Cloud can find something in the game that will allow him to kill someone in one combo from the start. We also do not know if the opponent is allowed to counter tag or if they actually have to take the full combo.
Playing Skullgirls which I'd say was a better Marvel than Marvel 3 (assuming you preferred MvC2 which was more reset heavy like MvC:I and unlike MvC3 which was mostly ToD combos).
