I don't think it would be hard to allow Piccolo to transform into his huge form. They could just make his model into a normal Half-Life sized model. I think a member of the ESF team posted somewhere that by Beta 2.0, all or nearly all of the characters will have all of their transformations. (i.e. Frieza's 4 forms, SSJ2 and 3 and such.) But I don't think Piccolo really needs the Mouth Blast, hes got enough special attacks already, maybe if they removed the Scatter Shot or something.