Aaaaah my 2nd favorite class of all time:

Haste, refresh, phalanx, Enthunder, Enfire, Enaero, Enstone, (etc), Debuffs and Enhancements, etc etc etc.

RDM would be the perfect idea to actually introduce SUPPORT as a role for the DF. you can literally do anything as an RDM, so give us that option. The biggest roadblock from RDMs being true RDMs in FFXIV is the DF.