I'm telling you, I've played on WOTLK private servers for so long. I always used shadows one notch before disabled even with my extremely powerful RIG for gaming.
Even on this private server Warmane I noticed how much shadows crippled performance ONLY when a lot of assets were on screen, things like Raids, WPvP ETC... The same still persist in Warlords of Draenor today, the issue is exacerbated because graphics are now more complex, maps in the new zones have WAY more Polygons compared to WOTLK, the new character models and overall engine is revamped requiring even more draw calls per scene.
Now you get into Ashran with hundred of Alliances and hundred of hordes fighting each other with 50 Death Knights using undead Army like animals and you will have such Draw Call bottleneck, no matter the CPU, and it will get worse the more shadows you have as this will have to be writting on each freaking ghoul, character, Pyroblast and tree on screen. Considering WoW is a very single threaded game with an ancient graphics engine I'm actually impressed it is actually playable at these circumstances even with skylake CPUs.
Hard to believe, excuse my skepticism but I'm willing to listen to any evidence if presented. Although I don't see how that wouldn't change what I said above.
Edited by Dargonplay - 8/19/16 at 9:53pm