They're basing Thor's look off of his current appearance in the Unworthy Thor run (which is awesome, btw). I think all three characters look great and personally, this is getting me crazy hyped for the film.
As for the Iron Fist stuff... I just... I don't even know where to begin with this level of stupidity. I understand why people complain when a character is cast as a race other than they are in the source material, especially when it's a case like The Ancient One being recast as a white woman, or the Gods of Egypt film where the whole Egyption Pantheon was cast as white guys...
But complaining that a character is cast as the same race as they are in the source material, because you THINK that they should be cast as something else, even though doing so would most likely result in the SAME people complaining that the character is a stereotypical "Asian Kung Fu Master" trope?
Utter stupidity, I was hoping that we'd leave this "Everything is offensive" mentalility behind us...