This is kind of determinant by what changes in tomorrow's hotfix for Sage gear. But it's already looking like a 21% reduction in general damage.
Overall, the idea of tribrid is both nice and viable, and it can definitely work easy for Iop. The only reason I'm hesitant is because fire doesn't bring anything unique to the table, and there's almost never an instance in which an enemy is heavily resistant to both air/earth or both fire/earth.
That and Iop's Wrath consumes WP, to which the class is also extremely WP driven with Jump and Increase. The spells you would want are Judgment for AoE ranged damage and Thunderbolt since 12 AP lets you triple Scalding and then Burning. Boltsword is slightly less damage than triple Judgment, however it doesn't cost any MP and it's a lot easier to hit the enemy without hurting allies that may be standing behind them.
It's a good idea though, and I'd like to see it enacted.
This post has been edited by Brokonaut - September 25, 2016, 00:33:53.