They'd have to dumb down the intensity that is this game, especially during insane mode. PSP doesn't have much RAM to go around, and playing online would be a mess unless they were to get rid of quite a bit of content.
NGP on the other hand will show the true beauty of this game. I highly recommend getting it as it's really fun playing it on the iOS device, although slightly laggy. It's still in the "prologue" stage.
Phantasy Star Portable 2 Partner Card Name: Xelor. Phantasy Star Portable 2 Characters: VAmar Xel, RAcaseal X-Oul