How about you frame the back wall? Add 2 Japanese Blueberry bushes/trees to either side of the wall to wrap your pool a little. With that much yard behind the pool, you don't want to close out the view, but by framing the wall, you can still see your property beyond the wall but add some "coziness" to the pool area. Beyond the wall, and to allow one to see the yard beyond the pool, add some bushes that grow about 6' tall such as yews or possibly oleanders (toxic to pets and kids if eaten!). You could even continue those plants on the sides of the pool to allow some privacy from neighbors (had to go back in the thread to see if there are houses next door, I think there are). Hardy plants all.
Good luck with it. With that much yard you are lucky that you can add some big plants and have it still look good without being overbearing.