There's the amount of coordination and that does kill some spontaneity. Example would be that the heroic player(s) would have to allow the villain to rob the bank successfully knowing full well that this leads to the funding of the giant city destroying laser that will be the battleground for the climax.
Also hoping the bank robbery doesn't lead to the villain starting something crazy like cutting off hostages faces and wearing them while the hero is paralyzed by the agreement the robbery would be successful. I can imagine the fall out.
"You said I would get away with the robbery!"
"That was before you starting mutilating hostages and river dancing in their entrails."
I'd like to give the benefit of the doubt that people could hash out an easy agreement but I've seen wild things happen in the MU* world.
I'm just spinning my wheels here thinking worst case scenarios that would make me die a little more on the inside. Villainous victory to a more awe inspiring epic loss is a good thing for certain.