Don't use XIV as a determining factor for your purchase... until it moves away from DX9 and into DX11, it won't matter too much once you reach a certain level of hardware. You may have already plateaued somewhat. With it's current engine, people can get acceptable results out of 5 year old hardware... just saying, you may be going into overkill if you use the current XIV as a deciding factor for a new GPU.

Google for benchmark comparisons on the other games you are interested in, or at least compare scores for something like Crysis 3 and such. Something like this article perhaps:
http://www.tomshardware.com/reviews/...ming,3451.html

Passmark posts scores from their benchmarks as well that can help you narrow down the field a bit too:
http://www.videocardbenchmark.net/