Currently Butterfly milking and piggy nibbling are ALMOST balanced. The new change meaning we get 5 milk per harvest instead of 4 is a step in the right direction, but if I had my way butterflies would be equal to pigs numerically in the rest of the ways too :)
It seems to me that there is no reason milking a butterfly should always cost 5 energy. We get pig nibbling down to two, is milking more difficult? If so, why? And a piggy super harvest giving 20 meat isn't actually equivalent to a butterfly super harvest of 20, as the milk is only worth 8 currants. So that being revised up to 25 would be ideal :)
Thanks for listening to me ramble ;) Best wishes.
~Liza