If Quicksilver had lightning bolts in his hair or as a belt, or most importantly if this was exactly how Aaron Taylor-Johnson appeared in The Avengers: The Age of Ultron, no fanboy freak-outs.
Instead it's Evan Peters (AKA: the future Mr. Emma Roberts) for X-Men: Days of Future Past. Bryan Singer is a more polarizing figure in the dweeb-o-sphere than Joss Whedon. They can't help but bitch. It is all they know, and they conveniently forget the seizures induced when Singer opted out of blue-and-yellow spandex for the black leather suits. He looks fine.
Grow up, fanboys. At least, try to.