The rule for auto-healing all damage after a long rest just feels wrong to me and I don’t like how it affects the pacing of the game.
Slow Natural Healing
This is a clarified version of the “Slow Natural Healing” rule from the Dungeon Master’s Guide, page 267.
The long rest is still an 8-hour period of extended downtime, as described in the Player’s Handbook on page 186. Characters don’t, however, automatically regain all lost hit points at the end of a long rest. Instead, the hero can spend Hit Dice to heal at the end of a long rest, just like they can during a short rest.
Each character still regains spent Hit Dice (up to a number of dice equal to half their total Hit Dice) at the end of the long rest.
There are times when the GM may award you additional Hit Dice after a long rest – for example, after staying in a completely safe and comfortable inn instead of resting on the road – but this is totally at the GM’s discretion.