See, I'm kinda 50/50 on the matter. Shang being able to morph into anyone and link strings together shows immense skill, but at the same point, it'd make him ridiculously powerful. Why would you play anyone else if you can morph into whoever with a 35% damage boost?
It'd have to require meter, that's the only way to make it fair, but even then...Shang would NOT have any bad matchups.