Do you want to play the game or get max FPS? An i3 with 8GB RAM and an R9-280 (or NVidia equivalent) will do just fine. Hell, I run WOW and Archeage along with all the browser, teamspeak, mumble (yes, 2 chat clients) and email in the background on a i5 4670 with a R9 280X and AA needs a lot more grunt than WOW does. (I run all my games in maximized window on a 1900x1200 monitor, so I can swap between them using the task bar, instead of alt tab).
As for 'needing' 60 fps, you don't. Most movies are only 24 FPS. I'm not saying smoother isn't better, I'm saying that you don't necessarily need it to enjoy the game. What you want is to stay above a minimum threshold (25-30 FPS), not constantly be at a maximum.
For the doubters, look at the centre of your monitor and move your hand long the bottom. Bugger me, it's blurred and that's real life!