A disarm as a standard action allows someone to attack and disarm with one roll and leave them disarmed until there next turn. Thats much more potient.
Yeah, I missed that! I still think it's probably about the same. On the one hand, if the PC misses a Kuo-Toa and still has a minor action, he can pick up his weapon. (Charging Kuo-Toa may be a bad idea!) On the other hand, the Kuo-Toa can act normally - that means dealing damage - each round, while the at-will disarmer can't.
The at-will disarmer, if he has a buddy who can move the target (or is willing to spend an AP), might be able to get rid of the weapon before the target can do anything about it. Then again, the target might have an ally who picks up the weapon before the at-will disarmer can do anything about it.
No I was using it is an indicator of your motivation behind wanting the player controlled standard action version which lets somebody easily snag the weapon out from under the target without any opportunity by the one most likely to have it.... sorry if I was judging your motivation incorrectly since that doesn't seem to be the case.
My motiviation is to put the fiction of the game ahead of the mechanics. If you think disarm is reasonable, then you should be able to attempt it, and it should have some impact on the outcome of the encounter.
(If disarm doesn't seem reasonable, resolve it that way: "That makes no sense." I would have trouble seeing a halfling disarm a giant, or anyone disarming a phantom warrior who wasn't also a ghost.)
If that means monsters who rely on weapons are weaker, I'd rather just lower their XP award by a level's worth or two instead of saying, "No disarms", or "The only way to disarm someone is to kill them".