My friend did put a good counter point to this though... "thinking of the longevity of the game, would you want to listen to the same dialog day in day out when you're grinding hard mode FPs?"
Yes. Because those story's change depending on who you are grouped with, as well as the FP have different routs to completion.
If they needed more group content, then they should have added a third route to existing FP. Perhaps multi-branch points throughout. More than one Discussion point.
To do such a great FP, with multi-branching layouts and routs, then just toss in some rooms with mobs in it later is a real letdown.