It was the scarcity of herbs. One Full Health potion required 3 pieces of 2 herbs, of which is was only possible to pick 3 per day. (It cost 2 of each to make a Hi Potion, and then another one of each to make a Full Health potion out of that)
And money was pretty scarce too, though I admit I had enough for several potions. As I said, it do think my resources would have sufficed in the end, BUT of that, I had no idea while I was playing. So the sense of confinement and fear to paint myself into a corner and end up with a cursed save was very much there, and is did tear very much at the fun of the game. I felt I didn't want to explore, and as I used 2 or 3 potions in a dungeon near the end, I was constantly worried that I'd end up standing before the final battle with too few potions, having to replay the entire game.
In-game worries is one thing. But this was a game-save technical issue, similar to the worry of a crippling bug. Lifting the forced limitations of healing wouldn't have made the game worse; it would have made it much more entertaining.