Personally, I'm a bit against RDM getting a DoT, primarily because other jobs had lost their DoT and showed that it's not a necessary addition (See: Warrior losing Fracture, Dark Knight losing Scourge, Machinist... kinda losing a DoT and getting Flame Thrower instead) but I'd also argue that it'd actively remove RDM's identity to give it a DoT, in the same way that BLM getting an oGCD attack would remove BLM's identity.