3570k vs 7700k

Solution
I think it depends on the game. Bf1 and witcher 3 along with a couple others seem to offer a bit more performance on an i7 vs an i5. Many games still run fine on an i5. It also has a bit of ipc improvement so the cores are a little stronger and if looking to overclock it looks as though it's getting easier to hit 5ghz. More than likely a higher oc than the 3570k is able to reach so that could be a perk especially if playing cpu bound games where you're looking for high fps like csgo.

Gaming is just too broad of a term on its own and even if you build around games you play now, games down the road you may want to play may have different requirements in terms of cpu power to sustain smooth frames.
I think it depends on the game. Bf1 and witcher 3 along with a couple others seem to offer a bit more performance on an i7 vs an i5. Many games still run fine on an i5. It also has a bit of ipc improvement so the cores are a little stronger and if looking to overclock it looks as though it's getting easier to hit 5ghz. More than likely a higher oc than the 3570k is able to reach so that could be a perk especially if playing cpu bound games where you're looking for high fps like csgo.

Gaming is just too broad of a term on its own and even if you build around games you play now, games down the road you may want to play may have different requirements in terms of cpu power to sustain smooth frames.
 
Solution
Also depends what you are aiming for. If aiming for 60 fps/Hz gaming the jump will be far less noticeable than if aiming for 100+ fps for a 144Hz monitor. For high Hz Id expect a much greater jump in performance. This assumes your GPU wont hold you back