And I'm changing it.
Here's our map:
Spoiler Alert, click show to read:
I think I am going to make every little bordered region we have worth 650 denarii per turn in tax revenue. So when we annex more territory, income will increase. When we lose territory, it will decrease etc. Eventually I want to to implement a way for the Senate/Proconsuls to use public works as a way to increase income from certain regions, but that will have to wait.
We have 62 shaded regions, so that works out to 40,300, roughly what the Senate makes yearly. This change makes it so that as the empire expands, the military can keep up. With a base income per year eventually the Senate will reach the max amount of upkeep that can be paid and that will be the end of it. That is too limiting.