Actually I think that Possession does need to keep that disabling feature, even more since it’s now the only non-magic circle in the Cleric skill tree that can disable enemies that are immune to knockback/knockdown.
Even Mikos Hamaya now no longer hitlocks enemies (dunno about Cure; it seems Magnus Exorcismus still hitlocks enemies even with its 2 hits/second), so it can become a nice way to shorten time between Cooldowns, especially since now it’s harder to reduce incoming damage with defence-stacking.
As Clerics lack the standard ways of disabling enemies like Archers, Swordsmen and Wizards do for many of their Classes and skills, having at least one skill to temporary disable your foes is a decent thing.
The thing they should consider is making the channeling uninterruptable (except for getting knocked back/knocked down) again to make it easier to execute the skill till the end, otherwise the possible loss of damage is too great because of the low base damage per hit