No, Shang really has everything he needs; his skulls and his soul steal move.

Shang relies heavily on zoning/trapping his opponents with his skulls, mostly the ground skulls, up close, if your opponent blocks an incoming skull, you are at an advantage since your opponent is still in his block-stun while you can move (straight skull gives no advantage, ground skull gives an advantage, up skull an even bigger advantage).

Besides, for training Shang, its a must to learn at least important moves/specials of almost the entire cast because of his soul steal move and the damage boost it gives.

Note that the damage boost is HUGE. Not like the 3-7% you gain by Reptile/Quan Chis damage boost-moves, but 10-30%+ depending on the combo, EX: a Cyrax combo (1bar, 58%) will become at least a 73% combo (still one bar).

Also note that the amount of time he stays morphed can be increased by using the soul steal as enhanced version.