While the game engine can accomodate a pretty wide swath of character types and associated origins, I don't think it's possible for all of those types to exist
within one setting. Some tastes (like what
@Scribe and
@EzekielRaiden are espousing, as an example) are simply going to be mutually contradictory and impossible to rectify.
I mean, we
already have a system where a John Wick type falls off a building and survives. It's only 1d6 per 10 feet fallen. At level 10, that's only ~35 damage (+/- 11 points for the two-SD range), so as long as a character can take around 46 damage without dying, they can easily survive a 100-foot fall. A Fighter can achieve 47 HP by level
8, even with +0 CON. (10+6x7 = 52) Even the absolute maximum damage dealt by a 100-foot fall, 60 points, can be survived by a +0 CON Fighter by level 10 (10+6x9 = 64). If we go for a +2 CON, that Fighter can survive 90% of 100-foot falls by level 6 (12+8x5 = 52), and absolutely all such falls, even all falls of up to 120 feet, by level 8 (12+8x7=68). All characters can survive a fall of any height, no matter how much damage it deals, as soon as they hit 121 or more HP, since the maximum falling damage is 20d6; a Fighter can hit this with +2 CON by level 14.
So like...if your issue is that John Wick surviving a fall like that is impossible for "mundane" characters to achieve,
you already have a problem with 5e. Because that's something that a pure single-classed Champion can achieve easily. A Rogue with +2 CON can do it by level 16. Even a d6 martial, if one existed,
could get there with a +2 Con, but it would only happen at level 20 (8+19x6 = 122). So like...as soon as you hit the mid-teens, even with the allegedly oh-so-grounded 5e, we are already getting things that cross the given bright line of unacceptable "supernatural" results coming from absolutely nothing except a lot of martial training, and any character that cares even a little bit about Constitution is likely to get there.
What do you make of this
@Scribe?
You can have a game engine where a John Wick type falls off a building and is fine, and a John Wick type falls off a building and is mortally injured, but not at the same time. Unless you're willing to accept level difference being fundamentally different genres within the same setting.
I do think that there is a direction this could be fulfilled by, but I also think some would not necessarily accept it. Specifically, the use of "novice level" rules to stretch out lower levels as long as humanly possible. That would let folks keep their stapled-to-mundanity characters, but at the price of basically saying higher levels aren't for them, which sucks. But outside of that, I agree, I'm not sure there is a way to bridge this gap.