DX12 Borderlands would be amazing.
I'm not disagree with you in the slightest, it's just that increased graphical pretties aren't really the priorities of DX12. Under-the-hood optimisation is. Eg DirectCompute is the secret to the current gen consoles' success, letting them squeeze so much out of under-powered hardware. DirectCompute is one of the key features of DX12. Just wait until we start seeing PC games built from the ground-up on DX12 or Vulkan, 4K on a $600 GPU will be much closer reality!
Better CPU multi-threading is also pretty exciting. Just think of how much more shit you'd be able to have on screen, more advanced physics, more intelligent AI. Future gen strategy games will be next level! The potential of our i7's will finally be realised!