Elaborate backstories and detailed campaign histories bore me; Its too much exposition. I prefer the “story” to happen at the table. In gaming, I seek the shared experience.
The longer the character creation , the greater the delay in the players and characters adventuring, facing situations, and confronting adversity.
I suspect that players view the time it takes to make a character as directly proportional to the perceived durability of their character; Dice and random elements are less likely to take out of play a higher durability character than a lower durability character.
First level B/X D&D and 0th-level DCC characters are the epitome of fragile characters: Dare to get attached to them, but accept the weakness of their mortal frame. You can make a low-level character in each of those games in 5 minutes or less.
Contrast B/X with Burning Wheel: a game with an involved character creation; You could rip through making a character in an 30 minutes, but I suspect character creation is an evening long activity for most.
In Burning Wheel, characters may appear fragile but player characters are difficult to outight kill. Yes, you'll get vexing injuries and carry those scars forward. But from those set backs you'll be poised for further skill growth.
Turn now to 5E , with its character creation system somewhere between B/X D&D and Burning Wheel; 5E is closer to B/X than Burning Wheel. Roll up abilities, pick a race, class, background, trait, bond, flaw, ideal, and equipment. You can get a character done in 10 or so minutes, but I'd imagine most will take around 30 minutes to an hour.
Low-level characters in 5E are more durable than B/X characters. You need to fail 3 death saves or die from massive damage. You also jump right back into action if you get a single point of healing.
Consider that the HP mechanism, as in each D&D iteration, models a binary state: incapacitated or full efficacy. You're either up at full capacity or you are down and in some editions dead.
Whereas in Burning Wheel, when you are hit, your effectiveness diminishes—you reduce the number of dice in your dice pool—and the system forces your character to make a Steel test, a kind of saving throw to see if your character keeps it together.
By design, Burning Wheel broadcasts the fragility of characters and D&D somewhat masks that fragility. There are short-circuits to the HP system in D&D— Save vs. Die, Save vs. Paralyzation, and Exhaustion.
How evident should a character's durability and fragility be? The abstraction of Hit Points places a veil over the details of combat. What does 8 points of damage look like…to someone with 4 HP, 8 HP, 9 HP, 16 HP, 17 HP or 140 HP?
What to Do?
First, assess the expectations regarding durability. And push against those expectations to better understand. What is the role of combat in this game? How does combat support the goals of the players? Is there an assumed parity of rules between PCs and NPCs? When a PC has a crossbow pointed at a startled NPCs head—even though the NPC has 100 HP —what is their expected response? Does that response hold if the tables are turned?
Without Morale checks—the Steel tests of D&D—5E D&D easily devolves into a fight to the death. Every. Single. Time.
For my games, I've added Morale checks. These checks are for non-player characters. See the 5E Dungeon Master's Guide for these rules.
For player characters, add a Steel test, or some analogue. I'm partial to Whitehack‘s special option:
Once per battle, when an attack would damage [a PC], they have the option to save. A successful save reduces the damage by d6 hit points, representing an adrenaline rush that enables the character to shrug off some damage from a single attack (it does not heal any previous damage). If the save fails, however, the character takes full damage from the attack, and if she has HP left, she is still knocked out for two rounds. If she gets negative HP, she dies without another save.
Buried within that rule I see a Steel test. The player, now realizing the severity of this combat, presses their luck with a Saving Throw to avoid some damage. The consequence of failure is 2 rounds of incapacitation. If you were already going to drop to 0 HP, Whitehack requires you to make a saving throw to avoid death. The above mechanic allows you to piggy back on that save vs. death and possibly stay in the fight.
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As a reaction to taking damage, a player character may make a DC 12 Constitution saving throw. On a success, they may spend one or more Hit Dice to immediately reduce the damage. For each Hit Dice spent, roll the die and add the character's Constitution modifier to it (minumum of 0). The character reduces the damage of the attack by the total of the the roll. On a failure, the character falls unconscious for 2 rounds. If the character fails their saving throw and drops to 0 hit points they also gain
two one failed death save.
A player character may not use this ability again until they've completed a rest.
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The above does not address all of the situations for Steel tests, but I believe pushes the spirit of a combat-triggered Steel test into 5E's combat. Character's spend one of their resources and assume some risk.
Ten Foot Polemic posted about honoring character death: give XP for performing funerals for the deceased.
Take a dead character's remains to a safe place with a church (or cultural equivalent) and you can buy their experience points on a 1:1 [gold]-for-XP basis.
In the case of a low durability game, consider bringing this into play.
I also add that there is a pernicious “level-up to unlock new features” vibe that I see in modern D&D and Powered by the Apocalypse games. Something along the lines of: “I want to see the mechanical impact of the character build I've worked through.” In the early days of our hobby, character death meant starting over at 1st level, or perhaps grabbing a hireling as your new PC.