They said the graphics code was a very tiny amount of the engines overall problem.
I believe it. It sounds like most people have their framerate issues in PvP, which is hardly a graphics load. Most good machines maxing out at 80-ish fps hints that that may be a limiter due to physics integrity or some such (think of the Skyrim bugs when you disable vsync), not CPU render load.
Framerate problems linked to shadows or PCIe bandwidth could likely be helped via newer APIs, but depending on their architecture it may well be even more work than usual, and most people's performance problems don't seem to be primarily related to that.