My take on how Good Biomes could be improved would be:
Benign Good Biomes: Friendly wildlife, wild plants and trees grow faster. Creatures get bad thoguhts for attacking and/or killing other creatures ("Urist felt guilty over taking a life recently"). Possible defense buff for all living things in these areas (ex: "the arrow stops a hair away from the deer, and falls to the ground harmlessly!") This benefit would likely be waived for attackers though, so hunters killing deer or goblins attacking your dwarves might find themselves much less dangerous than they had hoped. If dwarves harm nature too much by cutting down too many trees/clearing too much grass/killing too much wildlife, they might suffer consequences such as axes breaking on tree trunks, animals leaving the map/arrows auto missing or being deflected by animals etc. Dwarves in this sort of biome would be naturally happier, but the difficulty would come from having to moderate your tree/hunting industries.
Savage Good Biomes: Similar in many ways to Benign Good biomes, but with harsher penalties for transgressions. Mist might descend on your fortress and cause dwarves to fall into a blissful sleap. Faries might snatch baby or even adult dwarves away, perhaps leaving changelings in their place. Hunting too much will cause unicorns and other wildlife to actively hunt down dwarves instead of vacating the map. overlogging will cause trees to attack dwarves instead as well as breaking axes. Booze might spoil. Satyrs or dryads might entice dwarves to frolic and be merry instead of working, perhaps even causing them to permanetely abandon the fortress to live in the wilds with them (in which case they follow them off map)
In all Good Biomes I think what we should be seeing is the biome being a safer, but not necessarily easier place to live. Violence and heavy industry should have consequences, but in the same time this should not exclude the possibility of fairies, satyrs, dryads, centaurs etc from causing mischief-ie hurdles should be typically non violent in nature. The exception being savage good biomes, where hunting will be more permissable and predator animals will be present, and fairy pranks should be more severe, possibly even fatal, with the possibility for things such as abductions or the odd wild hunt.