Stronger guards, room description changes, more/better/more useful items made available at vendors, maybe more advanced buildings unlocked at different levels.
Maybe different buildings give different bonuses to the city.
Damage sustained by cities in Watcher raids de-level the cities.
Nobles and royals would be the "managers" of the cities, that might operate with a system similar to cabal army stuff.
There's all sorts of fun things that could be done with the idea.
It's not a clear-cut idea, but it provides a really interesting framework to play with.
An idea I had a long time ago was when Watcher/Syndicate raid a city, the city is then changed and the vendors sell different items and offer different things.
Does it benefit Knight to have Tribunal over Watcher? Maybe they’d help defend raids in that case.
Do Savant need something offered by a Syndicate specific shop? Maybe they’d help attack.
Is this just a watcher / syndicate / tribunal / noble thing? Does savant / warmaster / nexus have any skin in the game?
What kind of buildings, besides vendors?
What if the current state of the three main cities were at level 3 out of 5 levels. Level 1 and 2 are impoverished, damaged, crime ridden versions. Level 4 and 5 are polished, flourishing cities versions, with all the benefits of trade, vendors, consumables purchases, stronger guards, and whatever other benefits would be held at max level.
It'd give Tribunal and nobles some appeal, that's for sure. God knows they need it.
Cool concept. Maybe level 5 cities get smiths that can build weapons and armor from materials found. Perhaps level 1 cities have a publicmarket run by a corrupt thief who opens lockboxes for a graduating fee.
Maybe the Nexian General wants a new fiery sword so defends a city, while the Savant General has a horde of lockboxes and would rather aid the raiders.
Whatever.
Still a cool concept.
Added thought. Miruvhorian Noble wants his city to be the best, bribes Syndicate to sack Val Miran.
I think it's worth discussing the idea of a 'tax ' command available to Nobility, Royalty, and Tribunal Council Members. Maybe just available to Royalty and Council? Maybe just Council? Maybe there's different cities with different set-ups? shrug
The 'tax' would go on top of the pre-existing cost of goods and services within the city. The 'tax' would be the currency/pool which is spent purchasing upgrades for the city.
Maybe there could be in the City Center (which I'll go into detail about shortly) a dude that gives characters city quests, which when completed add to city funds.
Do knight/nexus/warmaster/savant have interest?
I think the diplomatic stages cabals have with Tribunal should maybe have more gravity than they do.
I think allies of the Empire should enjoy the benefits of that allegiance, while enemies of the state would incur penalties.
Off the top of my head, that could mean price changes, guards aggroing/assisting, maybe even places refusing to sell/service and drawbridges not opening.
What kind of buildings, besides vendors?
I dunno. Maybe like a city center which has more/less rooms based on the city level, similar to cabal headquarters and their areas.
Like...there could be a Treasury, which could provide better banks nullifying the crude interest / really good banks paying interest at the end of the month. Some kind of Guard room, where improvements/upkeep for guards could be paid for with 'tax'. An Economy Center room, where the vendors are upgraded. A Spiritual Office, where temples are upgraded - costs improved, upgraded priests can be paid to cast cool buffs, etc.
Addendum: An effect of banks in different cities having more/less interest paid in/out would mean then that a character would have to have separate bank accounts in different towns, as opposed to the current World Bank of Aabahran. I personally wouldn't have a problem with that at all. By its very nature it would likely orient people more around their hometown, which would drive up the players' interest in the goings-on of their hometown in regards to level (does my character live in a rich country or a 3rd world toilet bowl), geopolitically (who is my character's homeland cool with / at war with), character interaction with and interest in Nobility/Royalty, etc.