Oh yes dealing with morale is challenging :D I don't bother with checking every settlement. When I upgrade settlement I just see how much there will be housing and with this I build enough monuments by counting happiness they will provide. So every upgrade step with 10 pop you need 10 happiness, 20 needs 40 and 30 population 90 happiness and everything in between it's irrelevant. So I try to build first happiness to this numbers then add population. But it's really annoying, new model sounds much better.