Alternate recovery system

[Ainamacar]

TL;DR version: Reduce maximum hit points for short term hp recovery a la the playtest's hit dice, but treat this as an adventure resource rather than a daily resource.

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I've been pondering the hit dice system along with many of you since the playtest rules were released, and particularly about how to "square the circle" of the many different preferences people have with respect to mundane healing. Here's a very simple replacement for the hit dice system that I hope harmonizes some of problems people have with other recovery systems.

Suppose a character does not spend hit dice as a resource, but instead lowers their maximum hit points to heal themselves in otherwise the same way. To distinguish the normal maximum hit points from this temporary lower value, I'll creatively call the latter "pseudo-max" hit points. A character's current hit points can never exceed their pseudo-max hp, and each die of mundane healing reduces the pseudo-max by 1.

Unlike the playtest system a character may do this any number of times in a day as long as their pseudo-max hit points are positive.

Short rests otherwise work the same as in the playtest rules, but a long rest works as follows.
1) If the player started the long rest with at least half their max hp the pseudo-max increases by some modest amount.
2) The player regains all hp up to their pseudo-max.

Example:
Bob the elf wizard has a maximum of 30 hit points, and because this is the start of an adventure his pseudo-max is also 30. After a fight he is left with 13 hit points. His hit dice are d6 and he has no constitution modifier, so he decides to roll 3d6 to heal. He rolls a 12, so ends up with 25 hit points and a pseudomax of 27. The next encounter is closely fought and he ends up with 3 hp. He choose to roll 5d6 and gets a very good 24. That should increase his hp to 25, but since he rolled 5 dice his pseudomax is 20 and therefore he has 20 hit points. Fortunately he runs into no more monsters, and is able to take a long rest. Since he rested with 20 hit points his pseudomax increases (for an elf of his level perhaps this is by 7) and he wakes up the next morning with 27 hp and a pseudomax of 27.

So, what are the properties I like about this system?

1. Granting full hp means long rests take very little time at the table.
2. There is even less to track at the table than with hit dice or healing surges. Those require knowing how many you can spend in a day, and how many are left. Pseudo-max hp is a single additional value that conveys equivalent information.
3. Hit points remain a daily resource, but the pseudo-max becomes an adventure resource. This removes the "hard wall" where hit dice or healing surges simply run out and therefore the party rests. The choice to rest or press on could be interesting, and will have consequences. I hope this hits the sweet spot for those who want a little attrition because they feel it makes sense as well as those who just want full hp recovery because it's easy (and possibly makes sense). In any case, it's a kinder, gentler attrition.
4. As a corollary to point 3, changing the recovery of pseudo-max hp influences adventure pacing in a much less ham-handed way then directly changing a daily resource. I think many DMs could appreciate this.
5. Although pseudo-max reduction does not necessarily correspond with wounds, it is clearly thematically compatible and a wound/disease mechanic could be integrated elegantly.
6. Certain epic stories of attrition become possible to tell without making characters unplayable or ridiculously fragile. In particular, one could reduce pseudo-max hit points below half maximum, which would make one unable to increase the pseudo-max during a long rest. In other words, one is so worn down that the body simply cannot heal normally, even though the person remains functional.

It's not inherent to the system, but it would also be possible to explore the relationship with magical healing in interesting ways. For example, suppose a healing spell could either increase hp in the traditional way or increase pseudo-max hp by 1 per die in the healing spell. That puts the two on roughly the same footing in terms of adventure resources. A spell can, of course, prevent the need for mundane healing in the first place, effectively saving the character a reduction in pseudo-max hp (or hit dice in the playtest rules). In most systems with full hp recovery after a long rest an uncast healing spell at the end of the day is inert (except as protection against ambushes). In this system, however, one can defer the positive benefits of a healing spell until the party chooses to rest, and offset the cost of mundane healing after the fact. This further incentivizes the player to keep healing spells for combat and let mundane resources bear the brunt of post-combat healing, but keeps the spells worthwhile around the campfire. Plus, if the per die rule is used, this healing is fast because no rolling is necessary.

What weaknesses do I see?

1. Anyone who despises any sort of long-term attrition mechanic will not like this.
2. Without a true limit on gaining hp by reducing pseudo-max hp it is clear that characters, especially high level characters, will have a lot of potential mundane healing at their disposal. It doesn't come for free, requires plenty of short rests, and has built-in diminishing returns, but in some cases players might simply be too resilient.
3. Unsavvy players could really screw themselves by reducing pseudo-max hp too much, although the 15-minute workday tendencies of many gamers suggests to me that this would be uncommon.
4. We don't know how multiclassing hit dice works. In the playtest system the most straightforward way would be to track each hit die separately. That's patently fair but somewhat laborious. The other way is to derive a canonical hit die size for each character as a function of their many hit dice (e.g. the average, the most common, etc.) This is simpler in play but more susceptible to character build confusion and/or optimization. I enjoy optimization, but in this case it strikes me as pretty superficial. As far as I can tell the pseudo-max hp system only works smoothly given a canonical hit die, so if the arguments against the canonical hit die are compelling this system probably won't work.

I'm interested to hear your thoughts, especially from those of you with strong feelings about full hp recovery and whether hit point loss should have any persistent impact.