A while ago there've been comments that the AI would only build workshops, and usually disregard cottages. I never taught the AI to take improvement health and happiness into account. The improvement build AI is quite complex, so I wasn't sure how to correctly factor this in, and I could never manage to get the AI to stop building workshops (a new setup developed where the AI would keep forests with lumbermills together with workshops).
In the end I realised that even with unhealth in the picture, the AI was mostly right to just build workshops instead of cottages. Even taking final evolution into account (which the AI does), +2/3 production wins out over +4 commerce with less development time. So I think that mostly showed that workshops were too good. In fact, they are equivalent to mines now.
So I reduced base production to +1 again. There still stronger than before, with 1 unhealth being better than -1 food.
I still kept the AI changes that let it take unhealth and unhappiness into account.