And this is exactly the feedback I was looking for. TP issues, due to thinking my PLD the reining king of such already (though not to the point that I felt it needed addressing outside of improved spell usability), are something I overlooked entirely...
Ideally I would honestly like PLD's sustained AoE to have a bit more sustain than the others, but since this level of AoE currently comes free to them, the alternative being I charge them a portion of the TP cost per extra enemy hit, such that it (nearly) matches that of Overpower just beyond the potency equilibrium point of the two (rather than at, since it'll be inferior to Overpower beyond that point).
For example, I could simply make it...
"Sword Oath has been revised to increase the potency of all weaponskills and abilities by 25, and causes weaponskills to cleave nearby enemies for 25% damage at 25% higher TP cost per enemy hit (to a maximum of +100% TP cost)." At that point a combo cleaving 4 enemies would cost an average of ~130 TP (well, 126.7). It would still faintly outdo WAR/DRK in small cleave situations, while falling behind in large AoEs, but wouldn't have comparatively infinite TP by any means (actually, quite a bit worse than WAR, given WAR's Equilibrium). I'd prefer it to be a bit lower, however, since I don't want to put any PLD into a situation where he feels he needs to actually drop Sword Oath just for his TP, nor do I presently want to adjust potencies to decrease MT dps gap without anything Shield-ish involved and make Sword Oath just a cleave stance. 20% additional TP cost per enemy may be preferable, since Fast Blade already screws with my nicely rounded numbers anyways. (20% at least causes all integers, whereas 25% makes a 17.5 TP Fast Blade.)
Damn, I'm a little stumped.
