A rather large portion of adds are not immune to RoP, paralysis or leg sweep.
I enjoy finding out early expansions/new dungeons what is and isnt cc able with the above mentioned spells and always look to mess up casting. Let the dps and tank handle interrupting bosses or the less frequent larger mobs with immunities.
Theyd prob prune half of our cc toolkit if they gave us back an interrupt and what we have now is more fun imo.