Eh. I can't imagine there won't be a whole subgenre of retro doom clones in vr.
I think as far as pixelart is concerned it won't affect the genre much.
Plus, not every game made is gonna be vr. It's a rough technology still and even when perfected there will still be a lot of things that won't be exactly feasible within those constraints (2d platformers, for example) that will keep the pixel market open.