It took me quite a while to get through this but oh my, was it fun!
Maybe instead of unlocking the city you should have the player slowly unlock plot after plot and continue to develop their city VERY slowly.
If you have to juggle the assets you have down I think it would be very good if you could use multiple plots to generate more and more as the game goes on to unlock other aspects of the city.
Do you plan to continue working on this?