How's a cape a silly element again? No, really, how is Thor's red cape silly? Thor doesn't even have an actual "costume", it's a straight on asgardian armor that doesn't even need the kind of "rationalization" some authors use to make with the Superman costume for example.
It's really just annoying when people feel the need to cling on this "Silly Marvel good, Serious DC bad" idea that Bob seems to be an adept of.
Meh..
But anyway, that was a really nice trailer, never though I would be hyped for a Thor movie, since I mostly disliked the first one.