I know what you mean, I remember recently I was stuck in a dungeon (actual game escapes me atm) with a giant boss battle to my front and a long run back to a safe area with a shop for potions, luckily I make separate saves, very frequently but lost around three hours of game play. Maybe a once per day healing spell with a v slow regen of mana. This might be enough to keep players getting stuck but also manage to keep the idea that potions are not to just be squandered.
