Deus Ex Mankind Divided has DX12 and is already out.
And it worked like garbage. Every Dx12 implemented game I have played, it has lowered performance.
I didn't realize they patched it in yet. Aside from frame rate does it really make much of a difference visually?
DX12 is mostly there for performance. People with Decent to high end GPUs and older/less beefy GPUs can get much better results. And it won't be fully noticeable until we get actual DX12 titles instead of ones with support added later.