Guys I think would make for a good Mandarin.
Daniel Dae Kim
Depending on the aliens involved in Avengers
, it could set up perfectly for Mandarin's standard origin (ie, him discovering finding alien tech in a downed spaceship and mastering its use).
I think it's very important that they establish Mandarin is a threat with or without rings. I don't want him portrayed as a clown who just lucked into power, he should be extremely dangerous regardless.