The Avengers characters changed many times. The group went from being able to battle other worlds, to barely strong enough to battle Iron Man, or actually less.
Hawkeye and the Black Widow gave the group vulnerability, yet they also rise to take human abilities to extremes. Sort of the Bob Munden of archery, and the Widow clearly has a place in the group.
There are a couple scenes with Captain America out numbered, the Widow trying to jump on a scooter, etc. that gives rise to vulnerability.
Thor? Hulk? Only beings they are going to have problems with eat planets on a regular basis, or are Gods of Death. Oh, I forgot unstoppable juggernauts created by the All-Father and the like.
I really enjoy the movie on BluRay. Nearly 3D in 2D players.
Fury is a strong character, played well by Jackson.
I still think it's worth watching just for the Hulk meets Loki;-)
There are some slow parts. The dialogue between Loki and Thor gets just as old as it does in the comics.
I loved the line,
"Are you scared of a little lightning?"
"I'm just not overly fond of what follows."
Joss Whedon has directed a lot of stuff I really like. Buffy, Angel, and Firefly come to mind.
He is also a talented screen writer.
Other good lines:
Steve Rogers: Thor, what's his play?
Thor: He has an army, called the Chitauri. They're not of Asgard or any world known. He means to lead them against your people. They will win him the Earth. In return, I suspect, for the Tesseract.
Steve Rogers: An army. From outer space.
Bruce Banner: So he's building another portal. That's what he needs Erik Selvig for.
Thor: Selvig?
Bruce Banner: He's an astrophysicist.
Thor: He's a friend.
Natasha Romanoff: Loki has them under some kind of spell. Along with one of ours.
Steve Rogers: I wanna know why Loki let us take him. He's not leading an army from here.
Bruce Banner: I don't think we should be focusing on Loki. That guy's brain is a bag full of cats. You can smell crazy on him.
Thor: Have a care how you speak! Loki is beyond reason, but he is of Asgard and he is my brother!
Natasha Romanoff: He killed eighty people in two days.
Thor: He's adopted.