Balancing issue -  Captured Cities: When a city is captured there is a 50% unrest penalty which is hard to deal with in a small town - it either takes quite a few turns to make the city useful or you make the decision to Raze the city and hope there is suitable ground around it.  This makes sense and works wel within the game.

When a large city is captured it has almost all of the building built and even with the 50% unrest penalty the city is good to go and I do not have to do anything.  This defeats the negative impact of capturing a city.  

Suggestions to resolve -

1. Allow us to view the surrounding area so that we can determine if there is another plot of land to settle once we Raze the city. 
2. Destroy any unrest reducing buildings when a city is captured.
3. Change the % unrest based upon the level of the city (level 1 = 50% unrest, level 2 = 60, level 3 = 75, level 4= 90, level 5 = 110).  This would make sense as a large city is more loyal to their Sovereign. Now that may seem extreme at the higher level cities but some of the buildings that reduce unrest are already in place and the production of the city is already high. To address the high unrest you could give more options:
1. Spell to reduce unrest already exists and is a perfect fix - good for high level cities with high unrest.
2. Reduce unrest by paying Gildar - if a city is strategic you can start to pay off the locals and they will like you more.
3. Reduce unrest over time, every 10 turns reduce 5%