Fanaelialae
Legend
I definitely think it is meta gaming for a character with 121 HP to feel perfectly safe stepping off the cliff, but as soon as they are reduced below that it becomes a calculated risk because falling damage is capped at 20d6.I disagree. To me those tools ultimately are damage mitigation abilities (for at least slow fall and feather fall, this is explicit). And while the barbarian doesn't have those tools, what they have is the ability to absorb damage.
As far as how you rule in your campaign, you've already said, you'd probably let the guy live if he got knocked off. So to you, a character can only take advantage of his 'luck and skill' when fighting monsters, not when making planned, calculated, purposeful decisions to execute an action.
Separately, your interpretation of hp somehow makes barbarians the luckiest and most skillful characters in the game, which is...odd to say the least.
In addition, an accusation of metagaming based on current hp totals presupposes that characters have no internal awareness of whatever resource yo want to say that hp represent. This is silly. If that were true, no character would ask for healing, bc they're never know they need it.
And, at the end of the day, if the barbarian chooses to take that vertical shortcut, its not free. They still have to pay the hp cost. As such, if the goal of the gorge was to get the party to expend resources to traverse it, mission accomplished.
You don't need to disallow any internal knowledge of HP to not have a perfectly tuned awareness of HP.
Besides, as I've explained that's simply not how they work IMC. A character who falls 1500' and survives will feel lucky to be alive and in one piece. They're not going to believe that they can just teleport to the top and do it again without consequences, even if meta knowledge says they could.
They could use their HP if they got knocked off. They could even use them if they took a calculated risk (tried to jump on the back of a dragon as it swooped by). But not in meta gaming circumstances.
To reiterate my position, surviving a fall off a cliff is primarily luck. A character who acts out of arrogance and walks off the cliff because they are too lazy to climb down will find that their luck abandons them. You see this not infrequently in heroic fiction. Pride comes before the fall. Albeit, typically not in quite such a literal sense.
If it were just about the PC expending resources like in a board game, then sure, it might be reasonable. However, this is an RPG. The concern is one of verisimilitude. Not just your own, but for everyone at the table.
I believe thar dynamite deals something like 4d6 damage in D&D. Do you think that a high level barbarian should be able to smoke a stick of dynamite like a cigar and walk away mildly singed? I don't. To me that is absolutely absurd and cartoonish, and would shatter my suspension of disbelief. Much like a character walking off a cliff for no reason other than feeling lazy. If you smoke a stick of dynamite in my campaign, that character will die (though I would give a clear warning regarding this outcome).