What's your budget? What games will you play? Not all games require a powerful CPU and reaching record breaking FPS isn't that useful (though it's nice).
According to reviews, a GTX 1070 basically performs like a GTX Titan X. An FX-6350 rarely is paired with a very powerful GPU, but it can be done. An i7 would definitely be better, but an i5-4690K or an i5-6600K would be almost as good for gaming only.
If you overclock your AMD CPU (somewhat challenging with an inexpensive motherboard), then it should offer acceptable performance. How important is reaching full potential to you? That will dictate your budget. A CPU like the i7-5960X probably is the best CPU to achieve that goal, but it's hard to justify just to get a few more FPS.