i play for 15-20 days and my apartment is already full.
I managed to make it look like a regular living place but it was really hard make everything fit.
As houses have services like crossbreed and other stuff appartments don't , i really dont see why you couldnt increase the space slightly, it wouldn't make them compete in the same category anyway.
Nothing more, no more storage , just space increase.
2 meters diagonal would be just enough to make the place less crowded and less of a "slalom" to move in there.
it would have no impact on your server performances.
Please.