There are 45 locations (areas and missions), and 47 categories to farm for.
If you add summit, thats 46 locations so 1 will always remain unallocated if everything gets distributed evently and there are no duplicates.
After the gear set category is gone, and each set brand can have its own area to farm, summit is a better choice even though you might dont like it, because the targeted loot rotation pool got more diluted.