I disagree. The value is so low that I do not believe that it matches the RAI of the original spell at all. When you're likely actually casting it as a 2nd-level spell, you probably have a stat mod of +3 in your primary. That means you get 4d6 (14 points, average) healing out of it, and in combat that requires people to move through it and/or you to expend bonus actions moving it around, things which are not, together, trivial.
Given that even ignoring out of combat, it was totally plausible to expect 8d6 or more total in-combat healing, I cannot accept that this matches RAI.
Whereas Crawford's actual suggestion, of 2x stat mod, was quite close to RAI. Whichever nameless person decided on 1+stat mod broke RAI.
If it was for me, I would have also made it a bit more than just 1+stat, but it is not the exact amount which really defines the RAI.
I think the RAI is for this spell to be effectively a sort of "cure wounds that sticks around the battlefield for a few rounds" so that any PC who needs a bit of healing can go into the spell and get it.
Then, in combat how long do you think this spell is expected to last? It's a concentration spell, so there's a risk each round it will fizzle. Maybe if the Cleric is good and lucky, it can last the whole combat. But how does the whole combat last? I don't think that typical 5e combats last more than 5-6 rounds in most cases. And once again I believe for the RAI of this spell to be
in combat, not
in combat and a few rounds afterwards. They could have added a rule that the spell ends automatically "when the encounter ends", but that's really out of touch with 5e rules. I think the original max duration of 1 minute was probably meant to capture 99.99% of combats, but they probably didn't think about how much extra healing all the PCs can get every time a combat lasts less than 10 rounds, because if the caster manages to keep concentration until the end, all the leftover duration can be exploited.
The sad reality is that probably you should never design a spell like this. Since the mechanic of the spell is based on
turns, it is not going to work well out of combat when you actually don't have turns, even tho you can replace a turn with 6 seconds. The spell assumes a "cost" in PCs using their movement, and again you don't really care about action economy when you're out of combat.
The spell doesn't compare properly with Prayer of Healing which
cannot be used in combat and hence has a very different RAI. It's better to compare it with Cure Wounds/Healing Word at low level (when Healing Spirit potentially heals significantly more HP in total), and then with Mass Cure Wounds/Mass Healing Word at mid-high level, and here is where I see that I would have been more generous than 1+Wis, because once you can either cast Mass Cure Wounds (3d8+Wis to ALL your PCs in most cases) or an augmented Spirit of Healing (4d6 multiplied by 1+Wis) then the latter total is already slightly behind
and you still might lose concentration
and the healing is spread over multiple rounds
and the PCs need to use their movement (the only advantage of SoH is a more optimized usage of those healed HP).
