I play as piccolo... the only attack besides the generic beam and ki blobs is the SBC. He really needs more power up. In fact, the only reasons I don't play cell are 1) Piccolo's my favorite character in the show... 2) It's easier to press 4 for SBC on piccolo than some high number for SBC on cell (though I could easily change that in the options, I'm too lazy)
you know what'd be cool? A constantly regenerating life meter like maybe 1 hp every 2 seconds or so. Or maybe just a better SBC than cell's. Something with a bigger boom'd be nice =P