I would keep DNC mostly as it is. However I would change some things.

I would make Fan Dance 1 upgrade into Fan Dance 3.
Make Saber Dance oGCD, or make it have a chance of procing feathers if I left it on the GCD.
I would make each step of your dances pulse out a 20-50 potency AoE when you hit them.
I would also make it's AoEs ranged abilities so you didn't need to stand in the middle of a mob trying to see floor AoEs through your flashy animations lol.
Improvisation would either not require people to get full Esprit or would only require 1 person to get full Esprit.