I currently play WoW, Overwatch, and Witcher 3. I realize WoW is a very CPU intensive game, but with the release of Legion they raised the bar on their system requirements quite a bit compared to what it was 10 years ago. With my current set up, I'm playing on graphics settings level 8/10. When I move the slider all the way to 10, I notice a slight drag or sluggishness and it's bugging the hell out of me. Other than that I don't notice any performance issues in my games.
With that being said, my two 970's pump out a lot of heat and I feel like my system temps are hotter than they should be because of it. I wouldn't mind moving to one GPU to cut down on the temps and improve air flow inside my case.