FormerlyHemlock
Hero
You're changing the subject here from non-combat to combat but I'll go with it:
They're all unrealistic. I can name ways in which "Vancian choose your own opportunity" is actually worse than at-will (but probabilistic) techniques. For example, if the justification behind "you can only Disarm once per day" is "the enemy changes his hold to deny you the opportunity," why wouldn't I still be able to disarm another enemy 30' away who didn't see me disarm the first enemy because of an intervening wall, not to mention being busy with his own opponent? Why wouldn't I still be able to disarm a zombie? Zombies are too dumb to shift their grips. Why shouldn't I be prohibited from Disarming a skilled enemy fighter who knows about disarm maneuvers, even if he hasn't seen me specifically try it against anyone today?
If you wanted to add opportunistic attack options I'd say you should do it right: model the likelihood that the opportunity would arise (e.g. 25% per round for Disarm, or 5% if vs. an intelligent opponent who has reason to expect a Disarm and is actively preventing it). Then if the opportunity arises, I can use the technique at will, possibly with an opportunity cost (AC penalty). No Vancian resources required, and no feats required either.
This kind of thing is not suitable for core 5E but I wouldn't mind seeing it in a 5E Martial Maneuvers rulebook or something reminiscent of GURPS: Martial Arts, for people who want pure fightery combat to be more complicated.
Not having any combat abilities but ones which you can use all the time also makes no sense. At both ends, because repeating "At Will" attacks time after time is a cheap way to be predictable and have your opponent adapt to that, and that's an easy way to fail. At the other end, because virtually any martial school will teach you that some moves should only be attempted in the right circumstances and most of the time are not only not going to work but are going to compromise your defences. 4e resolved that dichotomy by allowing the player to choose when that opportunity came up and that's easy to criticise, but the alternative people seem to prefer is to either have no moments of opportunism at all or to make them present all the time - and neither of those things is as "realistic" as the 4e method.
They're all unrealistic. I can name ways in which "Vancian choose your own opportunity" is actually worse than at-will (but probabilistic) techniques. For example, if the justification behind "you can only Disarm once per day" is "the enemy changes his hold to deny you the opportunity," why wouldn't I still be able to disarm another enemy 30' away who didn't see me disarm the first enemy because of an intervening wall, not to mention being busy with his own opponent? Why wouldn't I still be able to disarm a zombie? Zombies are too dumb to shift their grips. Why shouldn't I be prohibited from Disarming a skilled enemy fighter who knows about disarm maneuvers, even if he hasn't seen me specifically try it against anyone today?
If you wanted to add opportunistic attack options I'd say you should do it right: model the likelihood that the opportunity would arise (e.g. 25% per round for Disarm, or 5% if vs. an intelligent opponent who has reason to expect a Disarm and is actively preventing it). Then if the opportunity arises, I can use the technique at will, possibly with an opportunity cost (AC penalty). No Vancian resources required, and no feats required either.
This kind of thing is not suitable for core 5E but I wouldn't mind seeing it in a 5E Martial Maneuvers rulebook or something reminiscent of GURPS: Martial Arts, for people who want pure fightery combat to be more complicated.