You have some performance lose because you making a dll call after dll and possible ArcDPS is in between which is another dll call on top of that you have 2 garbage collectors running instead of 1 and if it would be me I also would change in an upgrade matrix transformations with AvX2 code support(by the way AvX2 support is mandatory for win 10 systems because Dx12 us it internally) Dx912pxy real advantage is it running smoother because of multi threading but it has a lot of overhead because it is a proxy you have basically all textures and shaders twice in the memory. In theory you could make your own texture pack ^^. Well the Dx9proxy does also have some new asserts partial because there was no way around it I think especially the water shader broke with dx12, so they have their own.

What we do however need is better multi-core support and more gpu utilization (game is too CPU heavy) - this is something the d912pxy mod kinda fixes, if you have the hardware for it (you'll gain tons of FPS improvements compared to not having it, again, if you have the right hardware)

World of warcraft graphics overhaul