I still feel like its just as simple as buffing it, but if there is indeed "rest spam" going on amongst everyone, i would encourage a timer on full days rest. I myself spam it also. Big battle > save (cuz of crashing > rest > save, literally every large encounter, so it probably needs to be changed.
I wish there was a day/night cycle to indicate when we should take a long rest (could be during day or night but only once every 24 hours.) Even if they can't add the visuals for some reason, I still think they should make a once per day long rest the default (have a time counter somewhere) and have a menu option to turn it off for those who want the easy method. Would also bring more balance between Warlock and Wizard.
For reasons that are partially due to the lack of consequences/penalties and are also unrelated to the combat design, BG3 is actually the exact opposite, and it's been kind of a design whiplash for me. If you don't rest spam, you straight up miss out on a lot of story and cutscenes. For example, in my latest playthrough, I managed to get into the Druid's Grove and cleared half of the crypt before doing my first full rest, and it appears I completely locked myself out of interacting with Raphael at all because of it.
This is irritating. Pretty sure this is why I missed a lot of companion story as well.