Just unlocked Resolution and am tinkering with it now. At 100% TP and 1/5 merits, it does exactly the same damage as Spinning Slash. At 300% TP, it does roughly 1300 damage.

Witholding judgement until I have more merits into it, but since it's base is at least on par with Spinning Slash, I'm cautiously optimistic.

(In Abyssea as a PLD)