It seemed pretty interesting to me, if not a bit complex. My guess would be that magic/melee work in specific chains to trigger each other and deal more damage. Something akin to the combos on Drg/Nin/Mch, but they can lead into melee attacks, more powerful magic spells, or positioning moves.

I'm also interested in what may be the weaving of TP and MP. Casually using sprint as a Blm main is going to be a hard habit to break on Rdm if the physical skills need TP as well. I was never really a big fan of Rdm in other games, but if this can combine nuking and melee combos, I may have a new main. Also, I've been begging for a sword wielding dps for the longest.