Actually if you know your monsters weakness at lower levels lvl 20-30, you can do terrific damage to monsters with en-spells since even if you do 0 dmg, you will do at least 20 some points of damage per swing of en-spells with high enough enhancing magic. En-spells do not give TP to the monster. At lvl 10-20 i dont find RDM meleeing to be that big a deal unless they refuse to rest or manage their MP well, and granted /WAR, RDM can tank at certain levels or even main tank in dunes like a PLD of some sort. But its not expected.