Thanks for the answer, although I knew most of it from RTW, but I´m glad that at least in the building department nothing changed.

However, your unit example isn´t exactly what I asked, it refers to a hidden resource, they are unproblematic. But up to RTW 1.2 it was possible to have a unit to require more than one building (one of the stable line and one from the blacksmith line, for example), trying the same from 1.3 onward resulted in game crashes. That is the big question.