I'm currently building an extra residence because I need more population. I have enough for a second T6, but I'm running short of orcs, so I'd like a third armory but don't have the population for both an armory and a T6. What I can do is replace the ice rinks with residences, but slowly.
Or maybe I do have the population? I thought ranking points were equal to the number of population it needed, but that doesn't seem to track?