What are you trying to convey? If low magic and gritty, then healing is an issue, but if casting level 3 or 4 spells, in my game it would like this…
hour 1 “ healer, are you healing everyone?..give me a roll and don’t roll a 1…Great everyone is fully healed except Baker who took a spear through the arm, he’s at half health but can’t use that arm…you can fix him next round unless you want to do something different”
And that’s only if everyone was hurt…if only minor injuries…I’d ask them want else they where doing this round assuming everyone is healed.
Unless you are adding hard choices (a or b, life or death, hero or zero) to the game, don’t make it about annoying choices, and crappy rolls.
If you need it to be a plot point, add an ingredient needed per heal,
In an hour they can heal 200 hearts of damage but are exhausted, and magical creatures will notice such an expression of power…possibly come to investigate?
You could say those being healed this way need to rest…but they don’t in combat??? Or that they need to eat???
If concerned about having a resource lever to grind down the characters…it’s a different question. Make your combats more deadly, attack the healer, get your players rolling that death die!!!
Hunt the PCs, exhaust them, have them fear timers. Have effects that make all spell casting Hard until a good rest. Or nearly impossible.
Broken bones, blinded, feverish, poisoned, can’t focus, sore toothache, migraine headache…possibilities are endless!!!
Again, not an issue unless your PCs are running with 3+ hearts. At 3+ you need to start getting creative. And I suggest maxing it out, depending on role. But a guardian type with high armor, high con and 4 hearts…gosh but that just makes for long combats…add a couple of healers, and your just used up 2 hours with no changes.
Depending on game type, 2 hearts should be the normal max. Add temporary HP for big battles, or start nova strikes on PCs ( bad guys focus fire on one PC, so you do about 50 points of damage to one PC in one round.
“Kill the Mage first” should be normal reaction among intelligent and coordinated opponents.
Anyway I hope that helps, Getting your mind around a different but similar game, can be hard. Subtle differences get ignored but can make a big difference.
I heal A…I heal B…I heal A…rinse and repeat might be that you are not bringing the pain…make combat filled with choices.