As much as I’m digging 5th edition, the ability to completely heal all damage with a long rest doesn’t sit well with me. Here’s a simple method that allows for lingering wound effects without bogging down the game. It has the added benefit of giving new options for recovering from exhaustion effects (which is especially useful for berserker barbarians using the frenzy ability).
This optional rule allows for lingering wounds while keeping hit point recovery as is. To keep things abstract and simple, creatures take 1 level of exhaustion when they suffer a critical hit (instead of suffering increased damage) or drop to 0 hp. To offset the exhaustion effects associated with wound levels, cure wounds and restoration spells would remove exhaustion effects in addition to their curative effects. Cure wounds removes one level of exhaustion. Lesser restoration now removes up to two levels of exhaustion and greater restoration removes all levels of exhaustion.
Some special abilities and environmental hazards, such as starvation and the long-term effects of freezing or scorching temperatures, can lead to a special condition called exhaustion. Exhaustion is measured in six levels. An effect can give a creature one or more levels of exhaustion, as specified in the effect’s description.
Level 1: Disadvantage on ability checks
Level 2: Speed halved
Level 3: Disadvantage on attack rolls and saving throws
Level 4: Hit point maximum halved
Level 5: Speed reduced to 0
Level 6: Death
If an already exhausted creature suffers another effect that causes exhaustion, its current level of exhaustion increases by the amount specified in the effect’s description. A creature suffers the effect of its current level of exhaustion as well as all lower levels. For example, a creature suffering level 2 exhaustion has its speed halved and has disadvantage on ability checks. An effect that removes exhaustion reduces its level as specified in the effect’s description, with all exhaustion effects ending if a creature’s exhaustion level is reduced below 1. Finishing a long rest reduces a creature’s exhaustion level by 1, provided that the creature has also ingested some food and drink.