The problem with the engine is that it is CPU heavy and doesn't use the GPU at all, which was ok in 2000. Now all these new games utilize the GPU very well. You can pretty much spend $500 on a new computer, $250 being the GPU and run games better then the current generation of consoles.
I upgraded from gen 1 i7 to the newest one last month and it made a huge difference, like 30 fps gain. I have 2 gtx 780 ti in sli.
I do realize that MMOs need more CPU power because of all the players in the same instance.