I just hope that the foe proves to be enough of a challenge to make it worth bringing them all together, otherwise it'll end up being like a Fantastic 4 with more explodey-ness.
While it would be cool to see some team friction, I'd hope we don't have any "wow, are we supposed to believe these superheroes are that stupid" plot lines.
I would be all for the "well we have a few different legitimate ways to handle this, but some seem rather more sinister than others" type plotline. That would allow the different personalities to manifest and have some conflict, but have it be a legitimate conflict and not feel as contrived.
Would also be a great way to allow foreshadowing the Illuminati, which could then allow even more tie-in with existing Marvel universe franchises, and give reason to introduce other significant characters in the Marvel universe as well.
Anyhow, so long as their enemy is legit and there isn't any contrived conflict between the members, this should be a rather fantastic film. I am rather excited to see it.