What about a diffrent setting like a airship?Maybe if you had time and the airship blows up in I don't know and a fast boss that could be hard

I still think a great boss for Marvel vs Capcom 2 would've been Carnage-Zero-Phoenix. It's three different characters, so you don't lose that, and you could legitimately have them stronger than the regular characters, especially Phoenix. She could become Dark Phoenix at some point during the battle. Then you have Carnage and Zero, a Capcom and Marvel character before her, that almost everyone would like. Too bad they didn't do that though.

i forgot his name but i say blackhearts dad that's if any of you guys read the comic when punisher, Wolverine, and ghost rider fought him

You're thinking of Mephisto. Unforunately, most people will say that he's already been in a game, because they took Black Heart, put some red on him, and called him a different character.

I think Evil Vision's got a good idea with Pheonix.
Maybe they could run the Dark Pheonix transformation like Jin's Desperation power-up...

Have they used Apocalypse as a Final Boss yet? If not, he would be a pretty good one.

A better Magneto would be a good boss, or a Boss with every character in it! Have like a super power where the boss does a thing with all the characters super and uses it as a weapon!

A best boss foe MVC2 would be Shin Akuma, Onslaugh, and your teams should be the hard to win because they are much stronger and faster to beat them.

That would be stupid

Mainly because its supposed to be a regular 3vs3, not Onslaught, Shin Akuma and 3 other Characters. Onslaught himself is hard, and Shin Akuma with infinite supers is stupid.