I would hold off for another two years or so then maybe go with an AM4 R7-3800X (8-core Zen3) or comparable Intel setup.
That would then be very future proof and last 10+ years (or until failure), with a video card upgrade every so often.
*I believe the OVERCLOCK on a GTX1070Ti is applied in software and does not hold if the overclock program doesn't start. Just FYI in case you overclock but later wonder why it didn't hold if you reinstall Windows or remove some software.
HERE you see a GTX1070Ti is about 50% faster than a GTX1060 6GB:
https://www.techpowerup.com/reviews/MSI/GTX_1070_Ti_Gaming/30.html
HERE you see CPU scaling in GTA5 (2560x1600 but it's still being bottlenecked by CPU's):
https://www.techspot.com/review/991-gta-5-pc-benchmarks/page6.html
The i5-3570 is similar and while it does throttle the Titan the takeaway is it MANAGES TO GET OVER 60FPS.
So even when you do bottleneck it doesn't matter so much if the FPS is still good.
Those are just a couple examples, so basically you gain a lot more from a better graphics card than a better CPU unless again your goal is high FPS twitch shooters like Overwatch.
Even then Overwatch seems to get a good FPS with weaker CPU's (older benchmark):
https://www.techspot.com/review/1180-overwatch-benchmarks/page5.html