Originally Posted by Travesty
That's not really an Avengers gripe, that's a Thor one. You could still come into The Avengers without seeing Thor, and not have to worry about it.
That could be said of all the movies that led into this. You don't have
to watch them to get it. That doesn't mean the payoff of having seen them, like knowing what the characters are and are not capable of, shouldn't be considered relevant.
Now that I think about it, scratch the mind control not making sense. It doesn't until you see Thanos
show up, and realize the Mind Gem
on Loki's staff would explain his new power.