Dominating Blow spawn on rare mobs

This has been suggested before, but i'd like to suggest it again.

Dominating Blow is different from Absolution in that it only spawns minions on kill and with a 25% chance to spawn on hitting unique mobs, with nothing regarding rare mobs, this is a problem during campaign and with powerful rares.

Even a 10% chance to spawn a sentinel on hitting rare mobs would do wonders.

It's crazy how this isn't already in the game, when absolution already has it. Some of the rare mobs can be tankier then unique bosses, and when there isn't any trash mobs nearby your build is completely bricked.