I guess it depends on what you mean by "missing out", if the sim runs good with your 970.
On my end, I just went from an overclocked GTX 780Ti (which was on par with the 970/1060 cards +/-) and went straight for the 1080Ti (also overclocked) and the difference in FPS increase for me was night and day really. Might also add that I went with 32 gig RAM.
One of the reasons for me going for the 1080Ti is because I also play VR.
In any case, you will get a nice boost in FPS even with the 1070, but now that AMD is almost ready with their new VEGA cards, I'd hold off just a little longer to see what they can bring to the table (which in turn will maybe cut down the price on some of the GTX cards). :)
Then you will have more options.