As for those 5 job specific abilities; I have also been thinking about it and I believe this should be the 5 abilities when you become RDM:

lvl 30---> Cure II or some potent healing magic (since GLD/CNJ = PLD the only there option is GLD/THM which means no healing magic for it)

lvl 35---> Lightning II or some powerful attacking magic

lvl 40---> ??? ability - this ability exchanges or turns all strength or some attribute (primarily from tanks gear) into INT/MND and the more the RDM uses magic the more enmity the RDM will receive (this ability is the key for RDM tanking to keep all the enmity as a mage tank)

lvl 45---> En"element" - this will raises RDM attack for more damage (of course it will work much better with lvl 40 ability off)

lvl 50--->. Phalanx - the supreme defensive magic (raises RDM defense for more survivability)

this is it for RDM in FFXIV what do you guys think??

please be gentle when you comment but I am eager to see what you guys think