From what we heard, DirectX Next actually fixes a lot of latency related issues that are present in DirectX 11 and earlier versions. The new DirectX should have lower driver latency something that developers have complained for quite some time but we are not aware of any major feature set that will come with the DirectX Next.
Since the Maxwell core launches in Q1 2014, probably March, support was not possible and most likely you will have to wait for Volta graphics to support it in a year or two. In case AMD’s Mantle delivers as much as 45 percent performance boost as AMD claims in Battlefield 4, this might put a lot of pressure on Microsoft to speed up development. This might force Microsoft to solve long standing issues including driver latency. On a side note, we don’t have any info on AMD’s DirectX plans, either.
Maxwell is expected to deliver huge gains in performance per watt and will put another flavour on the graphics market. It will also be used in next generation Tegra products and Nvidia is also planning to license Maxwell IP to other ARM players, taking on the likes of Imagination, Vivante and ARM's Mali business.