A wild leap, but I’ll humor you this time.
So, that isn’t as easy to parse as you might think, so here’s what I think you’re saying.
*If a 2nd level spell that can bring everyone up to full* is no big deal, then making the spell simply heal everyone to full would also be fine. Since that obviously isn’t fine, the spell is a big deal.*
That doesn’t follow, at all. An equivalent argument would be, “because Expertise can sometimes make it so that only a roll of 1 can fail on some checks, it might as well just say “you automatically succeed on all checks with this skill. Clearly, therefor, expertise is broken.”
* (note that I said “fewer/no”, recognizing that the dice make it uncertain how much healing the party will get, and the vagaries of combat make it uncertain if that amount of healing will be enough)
Because there is a significant difference between “has a chance to” and “does, automatically and without chance for failure to do so”.
However, a spell that did guarantee full health, with a casting time that precluded its use in combat, wouldn’t be a huge deal, as long as it’s at least 2nd level. If it has a combat useful function, it would depend on that to determine what level it should be.
Healing Spirit, at worst, could be said to be too powerful for 2nd level. I’d consider moving it to 3rd level, at the highest. It saves the group some HD. That isn’t a big deal.
edit: also, as [MENTION=6795602]FrogReaver[/MENTION] points out, it would have to scale with up-casting, in order to be even kind of vaguely analogous.
But... explanation was that it eliminated the short rest time and HD expenditure at the cost one one spell slot - not a spell slot of a given level and no mention of "uncertainty.".
"it gives you a short rest worth of healing at the cost of a spell slot rather than time and HD. Cool. So what?"
A short rest of HD would roll as many HD with as many modifiers as on the start and should come close to their total HP, not exectly but usually not egregiously off. Also the time countered is the same regardless... 1 hour minus 1min of needed time.
When looking at numbers of dice like 10DICE per character, is it really the "rolls can go wonky" that makes balance work? Would you judge a 20dice fireball vs a 40 damage firestream as balanced because the 20dice might roll under 40 damage?
the key point for me that balances and imbalances this discussion is that if i take them at their own assumption...
"it gives you a short rest worth of healing at the cost of a spell slot rather than time and HD. Cool. So what?"
Well, a full set of HD is available once per long rest and takes an hour and the HD only recover halfway after a long rest at that.
This spell is available as many times as they have spell slots of its level or above and takes only a minute and the spells slots all recover after a long rest
of course, depending on character the short rest may produce other significant gains as well but also, that one hour vs one minute can be huge as far as ability to pull that recovery off at all and keep the objectives in play.
But again, for games with certain rest vs encounter standards and certain types or complexity of objective and challenges - how much any of this matters can vary greatly. It will not impact all games the same way by any stretch given the swings that games have in their encounter and pacing structures.
but hey, thats why its good that Gms can simply say "no" or alter "standard" things that trouble their specific campaigns, right?
For me this spell as presented was DOA after the first read. The revised "real intention" version still leaves it with a serious breakdown and so wont be considered for use either. maybe their third or fourth pass will make the cut or maybe i will decide to do something myself to tweak it if druids not having the healing prayer kind of heal is needed and i don't just decide in that case to give them "healing spring" that works surprisingly like "healing prayer" but with more druidly flavor.