Its totally unnecessary and together with dsync many block while at my face.
Obv you can keep block on bosses and elites but on trash its a total party-pooper mechanic.
I'm not killing 1-2 adds because they block and still have 25% hp left I have to move on to the next pack but then I lack the 1-2 agro in the next pull and in the next pull there may be more that block.
Cmon PA please there arent that many monsters that you'd have to redo.