This city bug again. Irritating. I've been unable to replicate it. Are you on Linux? Did you save/load?
I agree the buildings in cities are a bit poorly handled. For the next version I was thinking of removing them completely and just having an option to turn your city into a fishman city. It would then be able to be levelled up by you spending gold on it, each level gaining a new power it can deploy. A simpler mechanic, but the individual building slots never really worked out how I wanted, and it would let me tailor the powers unlocked a bit better, if they've got a proper progression to them.
Exploits of non-enthralled lords: Honestly your suggestion sounds pretty decent, and not too hard to implement. If they had a series of "events" they could trigger, based on their personalities. Maybe giving you a few options to exploit this, but mostly there for flavour. I'll have to look into it.
UI is being overhauled in the new version, so maybe the bits you dislike will be fixed. Scrolling menus are completely redone, because they were very bad, and most of the rest got a bit of fixing.
Anyway, thanks for the feedback and support.