If you want a melee rdm it's simple, make all his powerfull spell as an enspell (like fist of *** for mnk).

Slow stance : Next Hit will land slow on the target, occasionnaly enhance the power of slow if you keep hiting the target. (First hit: slow +5% , Occasionnaly 5% chance to add 1% slow each time you hit the target, Slow cap @10%).

Haste Stance : Next hit will trigger Haste on you and your party's member, occasionnaly enhance the power of haste if you keep hiting the target. (First hit: Haste+5%, Occasionnaly 10% chance to add 1% haste each time you hit the target, Haste cap@10%)

Etc...

If you make him to perpetually use his sword to trigger spells/ja you'll have a RDM melee !