I have no clue as to the why or how the AI deals with it, although they seem to do fine economically in my games. In the case of how useful building some off resource improvements are, I can give my experience with it. I only find the feature useful in the very early turns of the game (like first 50-70 in a normal speed game) and only in certain situations. For example, not researching mining and getting AH for resources. This leaves me without a true hammer improvement, but pastures give +1
and +1
, so it lets me get by till then.
In my opinion, pastures are the best out of the group (pastures, wineries, plantations) because of the 1
and 1 :hammers, while plantations (2
) are useful if you are slow to get education, but worthless afterwords since a 10 turn cottage gives that and a hammer.
These things let me guess a why, but I don't know the actual intent. My guess is that letting you build these gives some flexibility without forcing people to get education for commerce (plantation alternative), mining for hammers, etc. while having some weak hybrid improvements (winery, pasture) early for those who like them before they move onto the stronger hybrid improvements like windmills,watermills, and lumbermills.
Edit: Ninja'd by 3 posts, wow I'm slow
Edit2: I'm a little confused on resource spreading. So you need an improvement with a resource and another of the same improvement in an adjacent tile without a resource, or do you just need an empty plot adjacent to the initial improvement?