Hi,
As it seems, Microsoft prepared an answer to AMD's mantle:
DX12

It reduces lot's of overhead(up to 50%) compared to DX11

The nice thing is: it is compatible and runs with DX11 Hardware.
Which means, that an NVidia 400 is capable of running it.

So i thought, instead of wishes for a DX11 implementation, how about going for DX12?