kridak
Mez and root have cast times, and can and will be interrupted when mobs are on you. They're also highly resistible, and (excepting AE mez) only takes one mob out of combat. In the time you're trying to mez one mob, Inq charm can take out 2, sometimes 3 mobs at once. Charm will also shut down at least TWO caster mobs instantly -- root won't, no matter how many times you cast it.
Inquisitor charm was NEVER a damage spell. Anyone who thinks otherwise hasn't done the math: 60 seconds of damage every 30 minutes? It's infinitesimal.