I'm using a 1600p monitor and I'm seriously thinking about getting a GTX1060, believing it would outperform my current Radeon HD 6970 by a huge margin. I've tried to minimize the variables and I'm getting about 40 FPS in average. In the open skies 59, in the tower and more crowded situations about 30-ish, even less. For what I've learned, the GTX 970 should be able to run AH3 with most bells and whistles at 60 FPS on a 1080p monitor, the GTX 1060 has been told to be an even better performer.
Short answer: Very tempting.
However, if money is no issue at all, the GTX 1070 might provide better longevity in case your hunger for pixel count keeps growing.