Your 4690k is an excellent chip, cool it, overclock it. Most likely you wont notice an appreciable difference in games if you went to Skylake over say putting your funds towards a new graphics card. Based on past Intel releases, Skylake will be a small price increase over the current chips though expect some time for retailers to adjust to stable pricing after the initial early adopter premium.
My feeling is the 4690k is the new Q6600 chip and will last many yrs for ppl that don't succumb to the upgrade itch.
He hasn't bought the 4690k yet - sounds like he's waiting for Skylake 6600k.