After some consideration about it, it is wierd to spend $1300 on GPUs and $250 on a CPU. I will try to go for the i7-6700K for gaming now, even though many games take little influence from them. I saw what happened with AC: Syndicate on an i5 (4C, 4T) compared to an i7 (4C, 8T), and i don't want to have performance downgrades like that for spending $150 less on a CPU.
My old system has a 2008 Intel C2Q Q9550 @stock clock (2.8GHz), a Radeon R9 270 2GB and 6gigs of DDR2 @667MHz. I ran games like BF4 and The Witcher 3 both pretty much fine on it at high settings, 1920x1200. BF4 ran at 45-60fps (locked 60) and The Witcher 3 at 27-40 most of the time. The only issue was a lower frame rate going to 20-22 in Novigrad accompanied by stuttering, especially when it's just been loaded in, which didn't detract from the experience.
But, Watch_Dogs (And this isn't the only example, just the worst one) struggled to run at good frame rates even on Low, 1200P but i set it to a mix of Medium-High-Ultra, and dealt with really bad frame rates, which i don't want to have to do again. Anyway, using the mix, it ran at about 15-25fps in the city (horrible). Out in the countryside it was fine, however.