Herb harvests are pretty terrible, considering the massive number of herbs required to make tinctures, potions, etc.
Personally, I feel croppery should effect all crops (including herb crops) - giving you higher yield for higher skill in it.
Herbalism I and II should effect shucking (but this also should be increased a tiny bit) as well as allowing for the ability to plant herbs in the first place (maybe).
Either way, if this keeps up, tree poison (etc) will, when it gets on the market, remain INSANELY expensive to make / use
:-(