Feels like in-game quests tor guilds would be a nice addition to the game. It helps distract people from the constant grind, gives incentives for having a wide variety of professionals via quest requirements, and opportunities for interactions within and outside guilds.
NPC townsfolk seems like a plausible new mechanic/aspect to guilds for several reasons: (bare with me)
1. Can apply the human character model with a few tweaked AI interactions - walks inside guild claim only, can't open doors, shows no hostility (maybe coward in face of enemies)
2. Can have maximum amount of NPC townsfolk per guild, scaling with the tier of the monument, to prevent abuse or overload.
3. Can require upkeep costs either through food or wages or other requirements (e.g. preparations as "subscriptions from a doctor"), which could encourage in-game interactions between players.
4. Can be killed, which means they need to be protected during Judgement Hours.
5. Can be upgraded with specific requirements (e.g. AI specific to certain jobs, protected storage accessed via "password"), including soldiers.
6. Impose a penalty on the guild when an NPC is killed (e.g. bad reputations cause NPCs to be "afraid to come to the city"). So people intending to use these NPCs as guards need to be more careful with choices.
7. Makes each city more "lively" even when people in different time zones come online. Especially considering how the community is burning out, seeing more people - even if they are NPCs - can be a comforting sight.
Just throwing it out there.