i think its important to keep in mind that there are several different varieties of ability that interfere with the enemy's ability to use their stuff. also need to keep in mind that its not just enemy spells that you're looking to interrupt. item activations (particularly of consumables) are VERY easily interrupted. thats one of the main things you try to do with interrupts actually.
1) Full Stuns
- Mass Charm, Foul Grasp, Boulder Roll, Frost Nova
- prevent all actions, make enemies highly vulnerable for a couple of seconds
2) Micro-stuns
- Penitence, the proc effect granted by Regulus' Deadeye (yea i know it sucks)
- causes enemy to "hiccup", interrupting whatever they were doing for a fraction of a second. won't create a window of vulnerability like a full stun but will definitely disrupt the enemy's rythmn.
3) Interruption
- Pounce, Deep Freeze
- full stop on whichever spell was winding up but no consequences to other things. Deep Freeze has a pretty unique cooldown extending debuff which under certain circumstances can effectively act as a long duration Silence effect.
4) Silence
- Silence, the activation on Deathbringer (its an artifact)
- only stops mana abilities but still highly disruptive. better than Interruption or Micro-Stun, worse than Full-Stun.
so i don't feel like the concept of Disruption isn't fully fleshed out in this game. there's alot of stuff that causes some sort of disrupting effect. just getting to know the quirks is the important bit. abilities like Silence are designed to get around the fact that some alot of abilities are instant casting and cannot be Interrupted. abilities with cast times are extra powerful due to their vulnerability to Interruption and Micro-Stunning.