Random mercenaries are still not very useful, and now that there are a lot of mercenary types sometimes you get several mercenaries of the same role, or most of them in age 4. Because of this building saloon/monastery is still more of a gamble and very situational.
I think a better mechanics for the current state (with many mercenary types and overlapping roles) would be first draw maybe 3 or 4 random “mercenary regiments” of three with their own distinct unit combinations (same for every player), like the “hire mercenary army” cards. Let the player choose one of them and get access to the 3 mercenaries, similar to consulate or native embassy of US/Mexico. Switching can either be not allowed once set, or require some cost like changing consulate allies.
For example (just like the mercenary cards):
Highland: Highlander, Swiss Pikeman, Harquebusier
German: Landsknecht, Jaeger, Black Rider
Mediterranean: Barbary Corsair, Stradiot, Mameluke
Italian: Elmeti, Lil’s Bombard, (another new unit, maybe Genoese Crossbowman?)
North African: Barbary Corsair, Dahomey Amazon, Zenata Rider
Egyptian: Askeri, Mameluke, Gatling Camel
Indian: Arsonist, Jat Lancer, (another new unit, maybe a skirmisher?) ← I actually think Gurkha should be a mercenary
Japanese: Ninja, Ronin, Yojimbo
Chinese: Iron Trooper, Manchu, (maybe another melee cavalry?)
French: Fusilier, Zouave, Napoleonic Gun
etc.
There can be overlaps, and the regiments do not need to necessarily follow the geographical groupings.