Yeah that'd be a great idea. And as I previous mentioned before earlier in the topic, not only have a parade, but other interesting things going on town as well, that multiple people can join in on simply by being there.

Example: for Ul'Dah, Raubahn could send you on a mission to stop a street gang that is causing trouble. With every wealthy city, there will be crime you need to deal with.

Gridania: Opo-Opos (or other monsters) are causing a ruckus on the far side of the city. You're then ordered by Kan-E-Senna to go deal with the pests and bring back order in Gridania.

Limsa: A group of goblins has made their way into the city and are stealing supplies. Merlwyb orders you to find said goblins, and take them out.

Among other ideas for battles.

For convenience, instead of having to go and speak to Raubauhn or the other leaders themselves, you could have Guards shouting (like Battlewardens do) inside the city, speaking their orders. The difficulty could scale based on the amount of players taking part in it. And make different tasks for higher levels. Lower level players could take out the street thugs in one of these. But sometimes maybe the task needs to be set to attack deeper toward the leaders of these gangs/monsters.

Just some ideas.