This is not a bug/exploit in the rest system though. It works as intended. It replenishes your spells and skills. The real culprit here is how stealth works in this game. You could technically do the same with whatever ranged option the wizard has right now (crossbows? shortbows? Barrels?). Cantrips would work as well, I suppose. This is precisely how I killed the Phase matriarch. Turn-based, stealth, stealth ranged shot, restealth, end turn, repeat. You could do this in melee as well, as long as you are not in LOS of other enemies, which I tried in the swamp with the mud mephits. Killed two from stealth in melee and one in ranged, before actual combat was initiated. Even if you are in LOS you could pop an Invisibility potion. The abuse/exploit is the stealth mechanic, not replenishing your skills through resting.
Don't look at that hand (I like my overpowered Wizard)! Look at that hand (I don't care for Rogues/Stealth)! Haha. How transparent some people are. Just because this game has a LOT of issues than allows for game-breaking exploits, it doesn't mean *your* favored exploit gets a free pass/is working as intended. Why would a class ability such as Arcane Recovery exist in the game when you might as well long rest? Why would Larian bother to buff said ability on top of that? This is early access and by its very nature, a whole slew of things are *not* working as intended yet.