Immunobreak doesn't matter because a good mage lands debuffs on the first cast.
Making rdm wouldn't be hard, you just need to make it more useful than other jobs. This takes:
1) giving it some unique way of increasing damage (if temper was AoEable for example) or some unique way or increasing survivability.
2) making that way of increasing dmg more useful than all the others (possible example: a 60minute event you could only bring 6 people to with no where to lock buffs)
I wasn't sure which set of NMs were particularly resistant or downright immune to particular enfeebles, but I do recall hearing how the functionality of enfeebles and the nature of how they work would need to be changed in order to give RDM some limelight back. Subsequently, Immunobreak was introduced, but after a friend reported that even WHM can pull it off, RDM was put back into it's coffin.
So it seems RDM is back at square one in being virtually useless. Could there be unique methods of having them measure up to WHM or SCH without having some form of outside damage enhancement?