Obviously, good regions shouldn't be just "Bubble bulbs and unicorns." They should be more than that.
I believe that good/evil/etc regions are going to be replaced by more detailed things in the future, so I'm going to only suggest some stuff that can either (probably) be done or that should be done, anyways, so that the code is already in place.
Now to the ideas. I'm trying to make mine fit the "good" nature of the regions and still be Fun.
Land of Life--Some good regions will revive anyone who dies in the area, probably using the CE_RESSURECTION or whatever the tag is. The Fun is that it includes
all dead,
including hunted animals that haven't been butchered yet and sieging goblins.
Good Rains--Like evil rains, except probably without the bad thoughts (probably should be a tag in the raws for each interaction--e.g. [WEATHER_EVIL] (worse thoughts) or [WEATHER_BAD]--or else all good weather is pleasant). Also, instead of harming creatures, it helps them--e.g, healing, restful sleep, or a pleasant demeanor. The Fun comes from goblins also getting healed, people feeling so drowsy they nap in the grass, I dunno how pleasantness would be Fun, etc.
Fast-growing Vegetation--Self-explanitory. Crops grow faster, as do trees and shrubs, but the Fun comes from weeds springing up and...I dunno, probably more infections or something.
Any other ideas?