if they make 165, they surely have to move 170 up to 175. otherwise 165 will be full of WW cutting themselves into oblivion.
But to your question, 165 is the perfect place to have a GSPvConor superfight for the first ever title. I would hate this. but i can see why the UFC would love it.
What fighters would consider moving down to 165? Which WW currently cut the least? I've heard Gunnar cuts next to nothing, so it might be a good spot for him.
If a 175 is made, it would really shake things up as well. I could see Gastelum getting down there and doing really well. Also potentially even Whittaker!