A update and some balancing is what Piccolo needs. HR Goku was frankensprites with sprites from a few DBZ Roms and also had original sprites. The main idea for Goku was the style of the 3d games.

Piccolo is a rip and just programmed in to be playable in Mugen. What you can do is updating his moves with idea's taken out of the episodes and games. Some of his moves are to fast and some are to slow. It's a great addition but, needs some extra's.