I pushed the new aihint values to the branch now. I got rid of nearly all forced_after; very basic buildings have no more prohibited_till flags. I´ll watch how AI performs with the new flags during training rounds and adjust them according to my observations; when it works well, this can be merged into trunk.
The metalworkshop problem has already been improved by training. It appears only under certain circumstances: There must be lots of space (often on Big Eden, never on Dolomites); this only starts after several hours of gametime; and even then, AI doesn´t always build that many metalworkshops. I think now that probably this issue can be solved with more training and no coding changes needed. Other issues such as "gamekeeper but no hunter" surface less often as well now. The only major AI problem that can´t be solved by training now is road building.