MKII has some universal properties to the gameplay that would just about qualify it as broken. Some examples, you can't give a standing LK from a certain distance without taking a standing LK back, the juggling limitation properties that some characters can't do anything about, the Death Punch, etc. If you can think of a lot of parts of the system of a game that prevent characters from competing, the game is broken. Sometimes, there are just characters that can do things others can't, and those characters are unbalanced or locally broken.
Edit: More to the point, a broken fighting game contains systemwide flaws that hurt more characters than it helps. An unbalanced game is when some or few characters are either obviously or accidentally overpowered so far away from the rest of the cast, and does not have anything to do specifically with the system, but more the combos, speed, special moves, etc of said characters. MKII contains elements of both, MKT for PSX shows what happens when you add extremely powerful characters, it creates unbalance, but in general, MKT for PSX is not broken. MKT for N64 is broken.
