I use Win10 for gaming in VM and can confirm that it feels like native windows.
At first I had problems CPU wise but solved it setting custom CPU topology in virt-manager.
You need at least 1 real gpu for guest if you want performance and try to control host via ssh from guest. Tricky and could not work.
Besides gpu I pass-through ssd with windows itself for better performance but it is not required and you can install in a file. Besides I always can boot from ssd normally.
There are a lot of ways to setup network for guest. Unless you want its own network interface you do not need to pass-through real network card.
You can pass-through USB device at any time on fly or whole USB controller (in same way like any pci device).
For keyboard and mouse I use synergy. For some reason mouse through synergy has huge sensitivity in 3d games to the point it is almost unusable so a got separate one and pass-through it.
The only part I am still struggling is sound. You always can use GPU related sound system without problems but it is tricky to use hosts sound. I had to set 16bit 16k hz in windows and still there is a small delay (not noticeable unless you know).
There is an article on arch wiki that covers pci pass-through.
Intel Core i7-5820K
GeForce GT 710 for host
GeForce GTX 1060 for guest
