I'd wait even longer to be honest, the next meaningful upgrade from a 970 would either be in SLI, or go for the more costly 980ti, unless you can snag a 295x somewhere along the line (I personally would prefer 980ti over 970 SLI given the choice now, as 980ti is roughly on par with SLI 970's, which makes 980ti a better choice, but you probably will have to sell the 970 to fund the card).
The chip is aging, but it should still be adequate for your 970. For the last few generations CPU performance growth have slowed down to a near halt (increasing by mere single digit % each generation), and even then the CPU often is not a bottleneck as long as you have it clocked at a decent speed (something like 3.6Ghz+), so your 2400 should still be in no rush to upgrade.
Pascal should be a nice time to upgrade though, DDR4 ram should come down even more and there should also be a few more Skylake CPUs around to make a better decision. A decent monitor upgrade should also be in order (perhaps more budget G-sync monitors should be available).
EDIT: On actual gaming topic, I absolutely cannot wait for 2.3.0, that cube and Yang's Recurve is amazing...