Iwas referring to the arbitrary limitation of have 3 Jump cards.
But why is it arbitrary? It's not arbitrary that a 1st level AD&D mage has only 1 sleep spell per day. That's a part of the game balance (and then we tell a story about the ingame capacity of the mage's brain).
Dishing out 3 jump cards is the same. It's just that instead of telling the ingame story at the start, as a story about the capacity of the PC's leg muscles, we instead tell the story each time the possibility to jump a chasm comes up during play.
How often will a player ever attempt to narratively in-game jump a 4th time that day? Even though he is mechanically doomed to failure, because he had only 3 Jump cards and he used them all up? Why bother narrating a hopeless outcome?
Well, you might get such a narration - for example, if the player thinks that (for whatever reason) it is better to fall down the chasm then stay on one side of it (maybe a Balor is coming!). Or maybe the player knows (or hopes) that another player's PC will do something like cast a feather fall spell.
And, in-game, why is he doomed to failure anyway, since he's at full health and could feasibly jump a 4th time if he attempted to.
In game, he's not doomed to failure. It's just that we, the real world players, know what the outcome will be. It's as if the GM has an "unluck" card that s/he's obliged to play if the player's PC tries to jump (sort of the opposite of a "fate" card that - in some games at least - a player can play to make his/her PC's attempt an automatic success).
Any explanation is half-baked.
Well, I've just given some examples of how it might play out. I don't see why it's any more half-baked than the story AD&D tells about the size of a young wizard's brain.
In 3E, are there powers that are arbitrarily limited to 3 x day for no in-game fictional reason? Yes. Does 4E have *more* obvious and systemic examples of powers with such gamist limitations? I think yes.
I don't think anyone disputes that 4e has more mechanics that require the narrative explanation to be introduced
during the course of play, rather than being worked out before play. As a result, the correlation between mechanics and ingame causal logic is a lot more relaxed (as Hussar has pointed out upthread).
All I'm disagreeing with is the suggestion that a story to explain a mechanical limitation becomes more half-baked when it's told at the time of action resolution, rather than at the time of character building.