While creating such additions it's painfully required to consider the map's limits as well as the limits of the source engine. As I'm aware there's a predefined limit on things such as brushes and such that would eventually fill up as you're adding new things, yes? As a roleplay server it's important to cater to all sorts of roleplay. Most things like barracks can be done with some clever prop-work and not have to take up any of the map's available resource pool, thus letting said resources go to better things that could benefit the entire server.

Back to catering to all roleplay, it's important to sort of split the map's additions up "evenly". Not in a mathematical sense, but in a sense that if it doesn't contribute to the roleplay and such of multiple people, and types of people, it might not be worth it to waste resources on it. Instead, they could go to an addition to a building in a place that would aid everyone in their roleplay. Adding dozens of rooms onto the Nexus would be nice for the units and all, but that can be done with clever prop-work, and the majority of people who aren't units would never see those rooms, and thus, their roleplay would not be increased or altered at all after the addition of said rooms, wasting potential resources.

When you cater too much to one faction or group of people, the others will become restless and unhappy. It's important to find a nice middle-ground.

Hence why I said "if done correctly."

Stuffing them into a room or making them wait on the wall for hours isn't doing it right. There's got to be an active protagonist or antagonist, or simply one or more people consistently creating roleplay for the huddled mass of citizens. In an ideal situation they'd all flourish and their roleplay would blossom among one another, but it appears it normally takes some nudging, or simply someone willing to go all out and make the situation interesting. If you don't have people actively causing roleplay and interaction amongst the people, they'll simply run around, sit in a corner alone, and eventually disconnect.