Same Prob here.
Especially with egypt : Alexandria and Cairo.
Now in my new campaign i got the taxes to get them at 90 % order.
That made growth slower.
These are cities yes ; problem is same.
In castles however you cant adjust taxes.
Though i dont see a prob with castles; they grow just like i tech them up; just in time.
Keeping the bigger order , so less garrisson needed.
Also cities are harder to defend so need more than the 6 free upkeeps if in probably hostile territory.
one question though : The free upkeep for Castle : is it Castle based units or city based.
Another one : The Tabardaya or something from Egypt is build in City only but doesnt count with free upkeep units.
I can understand why the horses are not, but these should (i think)
posted the questions here cuz topic title is about balance so...