winter flame
Problem: certain shops are needed for missions, but are pretty bad compared to later options, forcing you to have at least one on standby, even if you don’t want it.
Solution: make upgrades also effect xp as well as gold, so they can scale with player level.
Add level caps like there are for units so you can keep it balanced.
broken pagoda
Not sure how they would add in a level cap code, given previous reports of spaghetti code from z2.
Instead, just crank up the costs of upgrading. Acts as a soft cap; to upgrade shops, you need better and more storage. That's already regulated by population, which slowly grows with levels.