Spellmaster is "really bad" and "shitty". LOL. The ninja variation seems average. You give up zoning for anti-zoning, which only seems useful in a handful of match ups. You can somewhat still play the basic mid range game as you would in Warlock, but you replace ground eruption with lift and slide, which are more risky but provide a tiny bit more reward in certain situations.
Warlock arguably remains mid tier and Shang Tsung's best variation, but if you intend to play a competitvely strong character who is centered around zoning, there appear to be superior options (i.e., Highborn Kitana, Spring Cleaning Cetrion, Outtake Johnny Cage) in this version of the game.