What's a mook, do you mean villains? I mean, people who know comics know who Malekith or Ronan are, so it's a bit of a dumb question.
They are extremely underdeveloped in the movies, so there is nothing to describe. If you are talking about the generic minions, well, yes, they are just generic minions.
Minions don't have to be generic, though. Look at Star Wars, or Lord of the Rings. People will dress up as a stormtrooper or Uruk-Hai even though they're mainly just mooks meant to be killed by the heroes. But no one's going to dress up as a Marvel mook because people wouldn't even recognize you.