Did you read the OP? It is asking for an extension of DS precisely so that players can play together.
And to reiterate what others have said, NPCs in a party can do far more complex mechanics than a human ever can. They are sitting in the same data stream as the enemies! In fact given how overscripted 14 PvE is, it would be trivial to have them move to safe spots before the cast bar has even started filling! You just code a trigger ahead of the cast.
But no, let's roll out this same rubbish so we can take another shot at players who don't meet some bizarre MMORPG purity test.