I generally agree that RDM needs a different party play focus that it's FFXI incarnation.

RDM is traditionally a jack-of-all-trades job that also specializes in multi/rapid spell casting.

The OP's melee-magic combo idea is a very good idea. If they really want to make RDM a front-line caster, adding an additional TP cost to all RDM spells would go far in defining that role.