In watching the last 20 years of home theater evolution, I don’t know that I would label anything as "future proof". NAD is a good choice, as Erik said. It looks like they have a generic architecture across all their products. They have released an upgraded 4K card as well as Atmos/Dirac card for their M17 processor. You’re locked into the NAD sound, which is excellent if that is what your looking for.
If you want everything right now, pretty much the choices are Marantz, Anthem and NAD (each with their own sonic signatures). If you want upper end audiophile level stuff, you will have to give up something. Classe Sigma only has 7 outputs and only 2 XLR. Krell Foundation is excellent and they already support 4K, but I suspect Atmos/DTS:X are going to be a long way away (if at all).