The one thing I wish they would make out better is the Stables. They seem hard sometimes to detect. This is only because the game INSISTS on filling in a lot of townhouses in the city for FANCY-LOOKS, which actually don`t have much to do with gameplay but clutter.
that would be stupid, imo, if they limited houses. Semi-realistic cities are needed for flavor. If anything I'd wish the city graphics were bigger, with more houses, like when you got to huge sizes the buildings started sprawling into surrounding tiles.
It should be obvious when looking at the wonders built, and what they popped. You know the merchants wont be in there, and you know they also threw their GP away when the GA starts.
The trick outlined by the OP sounds to me not just useful, but entirely justified.