You know who I'd like to see in an Avengers movie? Black Knight
Faiza Hussain would be a nice tag along character too. There's loads of members in the Avengers' varied lineup that I'd like to see in future installments, like Wonder Man, Quicksilver, Scarlet Witch, Wasp, one of Henry Pym's alter egos (Ant-Man, Giant-Man, Yellow Jacket, it's all good), Sersi, Vision, She-Hulk, Ms. Marvel, etc. The beauty of the Avengers is that they've had so many lineup changes through their almost fifty year history, that Marvel isn't tied down to a set cast list. I doubt that we'll see any of these characters in Avengers 2 - they'll probably keep the same lineup as the first - but we could in a third or fourth movie.