I can think, that it could be similary to the monk.
That some skills are again behind a other ressource (the only ressources, that the dragoon has, are the two dragon eyes, that comes from his jump, and the two Token, for two times make the rotation completly).

Or, to break the 5 hit rotation again into two parts. Like to the time of stormblood or hw.

The only big change i can image and would like is, to make the dragon eye skill easier.
Let us marking the Partner, like the dancer are doing it. So, that it didnt break the flow of action, by targeting a partner first. Or, by forgotten the partner completly.

And maybe, give him some aoe in the low lvl area (or have he it now?).
Most of the ARR dungeon are a pain, without the aoe attacks.