I've noticed when players rest they usually have several different options. Such as "Study Spellbook/Pray, Sit and Relax, Sleep" and have always wondered if there is any difference of effects between the option. It got me thinking. Currently I find the exhaustion script to be slightly annoying for one reason- and thats because it doesn't have a 'cap'. Some creatures out there strength drain and other things like that, Its very frustrating, at least in my own opinion, to have to wait 15-20 minutes in game to 'rest' because you received a very drastic boost to your numbers on exhaustion, sometimes multiple times greater than your own threshold.
I'm throwing out these ideas for changes-
1) A hardcap be placed on how high your exhaustion value can be. (A value of 100, for example, still means that 16con character would have to stand still for 15 minutes before he back to normal.) I don't know exact numbers, but I'd suggest something slightly above "feeling very exhausted"
2) Consider changing the different options to have a variety of uses, such as the following:
Sit and Relax: Resets their exhaustion, perhaps applies healing effects such as healing kits (Perhaps at a reduced value compared to an actual rest) but doesn't cancel current spell affects, or reprepare spells/abilities. (This might also allow fighter-types a bit of slack, not having to be so dependant on magical healing, but also limited and not actually replacing the needs for it.) I was thinking this function wouldn't be apart of the regular rest timer, and not sure whether or not it would actually need one. (Perhaps it would if it were to apply healing effects.)
Study Spellbook/Pray: Perhaps set a flat timer on this, 3-6 hours dependant on level (As the current rest function is, but maybe a bit longer wouldn't hurt to better match that of how spellcasting works) Otherwise it should work as normal: Resets exhaustion, applies healing effects, removes current spell effects and reprepares spells.
Sleep: (Never really understood the point of having it listed, other than for its emote function.)