By creating a Fencer class beneath it with adequate complexity in itself to be enjoyable at level 50, and then working the magic into a spellsword system, spending (based on macrorotational choices and build and the present situation) one third to two thirds of total time at melee.

Sadly, the spellsword system itself would require vast rehauls to introduce inherent by-element effects (not a mere rock-paper-scissors elemental wheel) into combat as a whole...