I got upgraded to 15J yesterday and as already known, right next to two toilets and a cupboard so quite a bit of foot traffic at times. Did move to the empty 15K and better if the divider is up.
Window wise, most of your view is the wing. You can see a but of scenery either side but pretty much 90% wing for all the flight. Fine on a night flight I suppose.
15K has space to get out with climbing over your seat mate (as did all seats in that row).

Only 3-4 people ventured through the curtain from WT. Crew used the toilets quite a few times as well and regularly checked them. Same with the cupboard.