On one hand that'd be cool, but the quest with P'molminn is optional. FFXIV doesn't really like to let you regress and do quests with characters prior to their current state. Instead they make those prior quests a requirement to do the new ones in the first place. They'd have to make it so that all players must complete the ballroom dance quest before starting Dancer.

Which is possible but I'm not sure they'd do that. There might be exceptions that I'm not thinking of so... who knows.

I'm cool with seeing older NPCs return in general. It's nice to see how the rest of the world has progressed alongside the WoL.