Just playing around with it in the trainer, the un-upped version just seems completely devastating to your own creature deck. Playing with a photon/fractal deck (i know, not the best example by a long shot) just is self-devastating.
with 23 photons on the board, 1 pandemonium resulted in:
2 unchanged (most likely lobo)
2 frozen
2 poisoned
1 gravity pulled
16 dead
Side note, what if the upgraded version acted like a mass upgraded chaos seed? Since entropy (like someone else noted) already has creature control, permanent control, etc... why not just chaos power every creature? That upped card can be treated like a fractal, high cost, and wipe clean entropy mana.
Or if its too powerful, do a mass chaos power with the ranges of -1 to 3 for attack, and -1 to 4 for power, just to deter people from making photon fractal pandemonium decks, because many photons would be killed in the process