After playing this game a number of times (I've lost count, but that's more a testamony to abandoned characters rather than any real expertise), I honestly don't know what the problem with minor potions are. They fill you up halfway, and frankly, that's plenty. I don't let my health fall any less than halfway down, and mana is usually around the same point when I suck down a minor restoration potion. You find minor reds and blues all over the place, and a single point in alchemy lets you cobble out as many restorations as you like. Plus, no shortage of vials because you can always buy reds and blues for cheap.
Heaven's Gift comes too late in the game to do much good. Yes, you can sit around and cast it; eventually you'll get a red and blue potion, make a restoration, and continue to cast until out of mana. You'll probably be surrounded in worthless potions and little piles of money. If you're really bored, you can fill up on potions this way, but for just a pittance of money, you could have gone and bought 5-6 minor potions and kept fighting.
Heaven's Gift, even at max level, rarely drops anything but potions, and I can't see that as cheating. You could have just bought the potions, and a lot more easily, I may add.
