I think that the thing most of us should be mad about is the fact the dev who are working on deus ex are from the same company as the one who worked on rise of the tomb raider. Meaning that the DX12 patch have a chance to be useless as it will bring little performance wise, or even be slower. The transition to DX12 looks a lot like the transition from DX9 to DX10. DX10 was not only bringing more eye candy, but also better performance on compatible hardware. Yet we were stuck for DX9 for a long time, The witcher 2 (2011 !) was a DX9 title, even though it would seem that CDPR had no reason to not use DX10.
The same story will happen with DX12, it might even be worse since it apparently require more work from the developers. It will actually be great to wait if that allow the people from Nixxes and other studio to learn how to use it. AAA developers are under a lot of pressure, and right now DX11 is just faster to develop for while also being the api with the most potential customers.
The 14nm era is likely going to be another long period like the 28nm era, so Titan x performance for the common people isn't going to happen anytime soon. And until zen actually hit the market, we don't know if taking advantage of more than 4 thread will actually be worthy. In 2006 dualcore were the mainstream gaming cpu, 2009 was when quadcore became the mainstream cpu, only 3 years. However Intel doesn't seem in an hurry to make hexa/octocore maintsream, and keep asking an hefty premium for it even though 7 years already passed. Until 200$ 6 core/12thread cpu become a thing, DX11 is going to stay for a while.