Healing has always been problematic in the D&D world because with Cure Wounds you can basically get an entire party up and running in a few minutes if you do things right. Healing Surges were probably the smartest abstract of that in 4E, even if they had some wonky bits, but at the end of the day I'm guessing there's some consideration for Adventurer's League/Pathfinder Society in these games: while a guy like me would love to have mechanics that force players to heal for a week or two, people who go to a game shop once a month for their only game probably don't want to waste that much time.
The Medicine change is a good one if only because it makes non-magical healing very viable, and thus allows people to always have healing options. The problem is that you can just
keep doing it, which I suspect is a feature rather than a bug: you're meant to be able to heal up to full if you don't have a Cleric, thus allowing you to get away from having to have a healer in the party. But for a guy like me, who wants more attrition... it's irritating. My solution was to limit the unlimited healing options you could use per-day, though I was looking at doing something a little more complicated with Medicine.
(I don't mind the DCs... I guess I just internalize that stuff much more quickly than others, so it doesn't really bother me)
Years ago pretty early in 5E I came up with "Wound Points", based on one's Constitution Stat along with using Wound Thresholds from SW:SE. It was at the least kind of complicated and I never got to use it outside of a test game. The idea of Strain from Worlds Without Number (Thanks
@kenada ) seems like an interesting way of possibly doing it. I know there are Vitality rules in the DMG that I haven't read because reading the word "Vitality" in that context just gives me bad flashbacks to SW:RCR.
But at the end of the day, it's a hard problem to fix given both the mechanical problems (magical healing on demand) and the non-mechanical problems (We live in a Pathfinder Society).