Capitols -
(Good idea?, more I think on it, more I like it)
What if the capitols were a combination of all three city types, then they would certainly stand out. The people that have a difficult time in the start would have their extra defence options as a fortress, mages could concentrate more on the conclave like options, the capitol would be able to tax & grow like a town
In 'almost' every instance I can think of, in both reality & fantasy kingdom stories, the capitol is THE largest city in the realm. By being able to build every building (or those offered by the three city distinctions), it guarantees you wanting to protect your capitol