You are sacrificing somewhere; most likely AA and console command modifiers to go beyond 'ultra'. Legion settings will be higher than current as well.
With basic ultra and no AA, I'm sure I can maintain above 60; but with beyond ultra (like increased spell effects, draw distances, etc) and the fancy 8x/8x msaa and bicubic resample, I do see below 60 fps and I have a oc 6700k and a 980ti.
If the poster has a z board and can find a healthy 2500k cheap, and pick up a cheap 960 or wait for a 1060 they'd be doing great; but they aren't bad now. I laugh a bit at 'tanked to 40 dos' when the consoles are doing 30 and people game just fine; wow is not a top end fps that needs über frame rates as much as it benefits from smooth frame rates.
Without a budget or info like current mobo, it is hard to give great upgrade advice to begin with. Limited budget, a decent gpu 60 series is the way to go, more budget more options.