The 2% unrest per city is a welcome balancing tool. I do like it. However, it needs to scale with map size. Other 4X games scale the "huge empire" debuffs according to map size, so should LH.
I think it could be as simple as:
- Small maps - no change
- Medium maps - first 5 cities do not add unrest
- Large maps - first 10 cities do not add unrest
The numbers may need to be played around with, but the concept is clear.
I was just playing a large map and owned less than 1/4 of the map and the unrest was out of control - I was razing level 3 cities simply because I had to. I don't spam cities or choose tiles with less than 8 total yield either (unless I am hard pressed for a city site early in the game). Currently conquest victory is less than optimally obtainable due to the unrest.