^Yeah, Quicksilver's is clearly an homage to his early-Avengers costume. I like it... (And at least it has more of a nod than what Hawkeye ended up with: S.H.I.E.L.D agent + snowboarder sunglasses.)
Whilst I agree that the whole spandex thing is a tricky thing to pull off on the big screen, Wanda did sport a couple of variants over the years and her more Romany-inspired (albeit cliché) look could translate pretty well, if they end up paying any sort of homage to that side of her:
Either way I think they'd be rather remiss not to have her actually wearing SCARLET somewhere i