Impact of Proposed Healing House Rule?

Question

What is the probable impact of the following house rule?

A Wisdom (Medicine) check can be used to restore hit points. This is a DC 0 check; the patient regains 1 HP for each point the result exceeds the DC. This check requires 10 minutes and one charge of a Healer's Kit.

I am primarily concerned about impacts on generally available abilities (like the Healer feat), and classes or specializations that would be negatively impacted by this rule. I'm not looking to take away player options and if this rule negated the benefits of, for example, a Cleric Domain or a specific Monk specialization then that would be a serious issue I want to know about.

Answer 1

Obviates small healing potions and decreases value of hit dice.

tl;dr It takes the place of small potions for healing between encounters, and all but ensures the party will be at full hit points between encounters.

Cheap Healing

The healer's kit costs 5 gp and has 10 uses. That's 5 sp per use.

Better than Potions

A proficient character can be expected to restore more than a potion of healing for a fraction of the material cost and has a reasonable chance to heal on par with a superior healing potion.

Better than Hit Dice

Offers comparable healing quantity to hit dice. Even an non-proficient character may get better healing than fighters or barbarians use of hit dice during a short rest.

It is more flexible it when it can be used than hit dice. This rule can be used in short intervals when a full hour is not available. When an hour is available this can be done 6 times in the same span of time for 3 gp. It essentially adds 6 nearly free hit dice to a short rest time span.

Can have more inventory than hit dice. Hit dice per character are limited to their level. This house rule increases the healing capacity of a character to scale with the available weight and small amount of gold.

Removes hit points as an adventure resource to be managed

This house rule would eliminate hit points and hit dice as a limited or scarce resource in an adventuring day. When handling a half dozen encounters in a day, the choice of if and when to heal is a real concern.

Per the Dungeon Master Guide:

The Adventuring Day

Assuming typical adventuring conditions and average luck, most adventuring parties can handle about six to eight medium or hard encounters in a day. If the adventure has more easy encounters, the adventurers can get through more. If it has more deadly encounters, they can handle fewer.

Given even brief respite between encounters, the use of the proposed house rule allows a decently equipped party to inexpensively mitigate all damage between encounters.

Answer 2

It makes the Healer feat (kinda) pointless

Healer feat says:

As an action, you can spend one use of a Healer's Kit to tend to a creature and restore 1d6 + 4 hit points to it.

That's a maximum roll of 10, not counting the additional points gained for hit die, granted. With a high Medicine skill, a good roll in the house rule could heal 20+ HP

Numbers-wise this looks like:

• House rule: 1d20 + Medicine bonus hp healed. 10 minutes, 1 kit charge. No feat required.
• Healer feat: 1d6 + 4 + patient hit die hp healed. Action, 1 kit charge. Feat required.

So in terms of healing output, duration, and accessibility, the house rule is preferred on two of three criteria and makes it seem like there's no good reason to take the feat. There could be some analysis to see at what point will number of hit die make the healer feat do better average healing, but I've not crunched those numbers.