Pig's base form: 1 more armor point Costs reduced by 25% Nether pig: (EDIT) Does not reduce energy costs, does not speed up energy regeneration, only buffs armor and speed.
i simply felt as if pig's base form was a little too weak, and i also thought that pig's nether form buffs were ridiculous.
I wouldn't want to improve Pig when I feel like Nether Pig is already so strong as is. Buffing Nether or the base form is not something I'd want.