I disagree about spell-slot/long-rest recovery costing inspiration points. This is 5e rule breaking and presents lots of other balance issues if you do this. Inspiration points are for rerolls only. Resting is classic D&D spell slot recovery. Refilling Inspiration at temples and such, especially with fast travel, would only allow mages to be SO much more powerful, thus throwing off the balance. Resting to recover spell slots is meant to be limiting to prevent OP mages. Plus, Inspiration points are supposed to be for good roleplaying only, as a reward for doing well in the game, thus giving you the ability to reroll for important moments, etc.
I just can't see any way that a real resting "penalty" that is true to DnD rules could be implemented that isn't awkard or forbiddingly resource-consuming, since the PnP solution itself feels like a crutch. It allready implies characters "meditating" or "preparing" spells while resting. All my suggestion does is put it into a currency a video game can understand. I don't think the inspiration thing would make mages OP because it still costs the players money and actual game time.
The POE/Pathfinder-Kingmaker solution to resting (basically rations) was a worthy attempt at making resting meaningful, it just ultimatively fizzled because it was incredibly difficult to balance/tune the cost/frequency of them. Diversifying this system feels like a decent way to improve on that. I could live without temples/inns but it would create a scenario where a player could get stuck and would have to backtrack.
I also think that adding "deadlines" to a videogame that doesn't even have a day/night cycle opens such a giant can of worms in terms of making the campaign feel coherent. How do you f.e. communicate the different time-limits in a way that isn't awkward at best and frustrating at worst? How do you differentiate between quests which are supposed to just "feel urgent" (tadpoles) and ones that have actual deadlines? It is a whole lot of work/Q&A to implement and IMHO can't really be simply tacked onto a game without a boatload of redesign and you are ALWAYS bound to miss something. Just take a look at EA and the amount of work still left to do with filling in all the blank spots in reactivity. Don't get me wrong, I'd love to see a game suceed in doing it - I just think it is reeeeeeally hard to do. Kingmaker had a system which sort of simulated the passing of time and basically had to engineer the entire campaign around it.
Fatigue in the game would be more true to D&D 5e rules. If you don't regularly eat and drink and rest you would suffer fatigue. If Larian implemented a fatigue system, then food would not be needed to heal. You could just do away with food healing at all. It would then be specifically for preventing fatigue or removing it. This is what it was meant to be in D&D anyway, not hp recovery. So, in my book, that would be way better anyway, more meaningful and realistic and would create a bigger difference between potions and food. It would give food a bigger purpose, which was the reason I suggested making food only recover HP in camp. Add a fatigue system, and do away with food recovering HP. I'm good with that.
In the same vein I think adding "time"-based fatigue is really tough to pull off in an RPG in a meaningful, fun way. Again, POE had an exhaustion system similar to the one you are proposing and tbh, it didn't really add anything and at best amplified the use of rest-spamming. The only reason why I am even bringing up exhaustion as a possible mechanic is because during some of my playthroughs I had characters downed 3 times during a fight to the point of it feeling like cheese to keep an enemy in place.
But ultimately, we HAVE to uncouple the dialogue/story/character development aspect from long rests. It's ridiculous to have a character hardly do anything and then say they need to rest just so they can spark a conversation. I've literally had sessions where I adventured for 5 minutes and suddenly they want to end the day. Dumb.
I sort of agree, but I can understand why larian is handling it like that as a story vehicle because it is the only place where you can get all characters together and you can control the environment. Maybe all it needs is a line like "Lets get back to camp and I will explain" to make it feel less dumb. You wouldn't have to end the day, just return to camp.