I think the main problem with RDM as a job is that SE has no idea on what this job should be.

1. If Rdm should be master of enfeebler - this position is easily covered by many other mage jobs. As other posters have mentioned, WHM, SCH, and BLM can cast most of the spells that RDM can and do a good job at it.
2. If Rdm should be master of enhancing - WHM and SCH can do just as good, have access to better spells, and get a lot of AOE spells more so than RDM. Composure only works on RDM self casted spells...which negate the whole point about being a master of enhancing - that only benefits the said RDM but not to the party.
3. If Rdm should be a melee mage - sadly this position is already covered by Blue Mage with far far better spells, some party buffs AOE spells, and much better damage output.
4. If Rdm should be the jack of all trades - well I think SCH pretty much kill this with a rdm set as support job, plus SCH can cure and nuke better than Rdm.
5. If Rdm should be a support job - uhmm hello there, most of RDM spells are SELF casted only and for some spells you cannot even use accession to help the party, plus SCH makes a better support job that complement WHM better than RDM can ever hope. Why would you make a job as support when most of their spells are self target and do not benefit your party members. The day of Refresh and Haste monkey is over - it's time for SE to take a long hard look at this job.

So what is RDM suppose to be? Why SE is taking so long at actually do some tweaking on this job (and Summoner)???? Please stop giving all the good stuffs to Samurai... or White Mage...