Two hour run time, and you have to introduce 5 heroes, and 2 villains, with a third who only appeared at the end of one. Not to mention, the others around it. yes the villain didn't get much development, but Lee Pace still did a good job. Nebula is out there for the future, somewhat set up by this one. I think it wasn't too bad considering you have tow hours to do that, still tell a story, get the audience involved in it. And you are doing this with a franchise, that other than hard core comic geeks, there is no familiarity.
It was a lot of fun, and these days, movies need that more. It took itself less serious, and even though this is a comic story going to big screen, it was still the most original movie I've seen in a while, and yes I'm biased cause I'm a marvel geek, working for the parent company, but still...
