Wow. Been a while.
The Thor trailer and Comic-Con stuff has made me all school-boy giddy.
What Whedon needs to do with his movie is make it a combination of 616 Classic Avengers and Ultimates, somewhat like the Ultimate Avemgers animated shlop. And the the first "villain" should be Hulk any way you look at it - because he was the first "threat" the Avengers took on (even though he was manipulated by Loki) as well as the first "threat" The Ultimates fought - That's the history of the Avengers. This is already set up in The Incredible Hulk when Stark comes to Thunderbolt and tells him he has "a solution for his Hulk problem," and slaps the Avengers Initiative folder on the bar. IMO the first act of the movie should be the assembling of the Avengers & the recovery of Cap climaxed with them fighting the Hulk at the beginning of the second act. The 2d half of the third act leading to the one big fight climatic third act needs to be something you want this team together for.
Now the villains we logically have:
1.) Loki should be in it. He is the cause of the Avengers fighting the Hulk to begin with.
2.) Red Skull would be a nice tie-in to the Cap movie.
3.) I can see a Crimson Dynamo - being Ivan Venko, keeping himself alive in much the same way as Tony did, from the wounds he received in IM2. Come on, nobody really dies in comic books!
4.) The Leader. He did come to being in the Incredible Hulk.
5.) Which means we could see the return of The Abomination.
6.) The Nine Rings Gang from IM. They could be a good "Terrorist" threat that involves SHIELD, perhaps backing the primary villain(s). Could have a tie to Red Skull, but the obvious reference is to . . .
7.) . . . The Mandarin. Would love to see The Mandarin. Don't wanna wait for IM3.
Looks like a nasty Masters of Evil to me. And, of course, we would have to have Black Widow turning traitor.
8.) They totally make something new up.
9.) Or just use Skrulls.
I want Carol Danvers!