It recovers one use on a short rest and takes two long rests to recover their full hit dice. The goal was to bring races up to match mountain dwarf, variant human & the like... None of those have a 1 per rest you can benefit from +2/+2 & medium armor or or "Feat: you gain one feat of your choice & can use it once per long or short rest". Stone's endurance requires a reaction & you only get one per round so if making a dc10 concentration check or bringing a 26 point hit down from dc13 to dc10 is your big concern the simple solution is to hit bob twice in a round as only one of them can theoretically get soaked if he has a hit die to spare after the free one. People weren't save scumming with short rests for stone's endurance before when it was 1/long or short rest & still won't be.I still have not heard an excuse for argumenting on a different presumtion than what you presented to us. And then you treated me as if I am wasn't able to read. But the mistake was on your side.
I am not sure we are on the same level about the definition of a 5 min workday.
In my opinion, It is the ability to burn all resources in a single fight. Recovering resources on a short rest exactly counteracts this. You need to take short breaks to recover some resources.
So what you propose was recovering on a long rest, and you could spend everything you have on healing resources in a single fight, effectively doubling your health. Recovering a tiny fraction on a short rest afterward does not help your argument. At least you can now say, that you did not nerf the free uses, so it is a straight buff... but it is way imbalanced and terrible for the game overall. I don't know why you think +1 to a stat and armor proficiency for a wizard is that powerful. Very useful for a wizard (that did not dump str to 8), yes. Nice to have +1 stat point on your main stat, also nice to have. Probably 5% chance to have your spells stick on target or make a con saving throw. But deciding between this and reducing damage - as you propose - a number of turns equal to level +1, so I do not actually have to make the concententration save at all - is no decision at all.
Also, stick that on an enemy spell caster with 5 hd and 30 hp and you will see how it goes.
I don't know how you could be so confused as to ask "So what you propose was recovering on a long rest" after I previously posted
Stone's endurance by RAW works like
I admitted a mistake earlier when I explained it, you keep attacking that point as if that since corrected mistake is a big bone of contention... drop it.