DirectX 12 itself is totally irrelevant. Both the PS4 and Xbox One are using GCN-based GPUs, and are capable of the same things, no matter if they use DirectX or OpenGL or a whole other graphics API.
But sure, DirectX 12 could improve the performance on Xbox One. It depends on how efficient or inefficient it is compared to Microsoft's current low-level graphics API. --- Super Mario Kart is the single best Mario Kart ever!
Killer Instinct has a lower Metacritic than Playstation All Stars. Is that mediocre too?
It's well know the Sony trolls will drag anything on a MS system down on metacritic with BS reviews, something the XBox community isn't low enough to stoop to. Just look how low Sony trolls stooped with racist comments and remarks because the PS4 didn't make Toy r Us's wish list for the holiday? That's pretty ******* pathetic to drag down a kids site and get it shut down.
As far as the game goes, that game is not complete yet and is still evolving. All the reviews are based on an incomplete game. I've only seem one publication even claim to be holding off on a final review until the game is complete.
The game is great, but you also need to remember that the game is part of a niche genre.
I DO want to play Killer Instinct whenever I get an Xbone and reviews aren't gonna sway me from that game.
But metacritic between PS4 and Xbone games right now is pretty low with most titles in the low 80's to mid 70's.
To say one's library is better than the others at this point is a lie be it PS4 or Xbone. --- PLAYSTATION PATRIOT