The RM is better than the BM and WM hands down as he has something to fall back on when his magic runs out, unlike the pure mages with their mighty cat claws and thor hammers!!! The only usefull spells that they have on him are LIF2 and NUKE, which you only have a couple charges of once you reach the ToF.

The Fighter and Black Belt outclass the RM as they can take/deal respectively, insane amounts of damage, to the point where no healing/nukes are needed. Why cast a level 3 elemental spell against monsters who will resist it (thinking ToF) than attack for a solid 200-2000+ depending on your leveles.

The Ninja is on par with the RM as he has hands down superior defense and a similar offense. This is offset by the RM's vast repertoire of more varied magics, the only useful spell the Ninja gets is FAST.