The exact issue with bringing up MGQ is that while it has difficulty, it also explains clearly what exactly the player's doing wrong without laying down a penalty to make correcting said error more difficult in the future. With SHRIFT, the penalties just get worse the more you fail, if a player's failing too badly and attempting a no kill run this cycle can be crippling if they don't use the pity points. Which in themselves penalize the player by preventing the best possible ending.
Imagine that, in MGQ you got a penalty applied to Luka that removed 10% of your health per turn, after you lost to an enemy a couple times. That's just happens in SHRIFT with the lust mechanic. In a tactical game like this, turns need to be taken to shore up your willpower and keep up with the demand for magic. Combined with a bit of bad luck and the player can be destroyed in one battle. Out of resources, too far from any safe areas, unable to win in a random encounter.
Toss on top of that luggage a grind for ammo and other resources. If you need to manage resources and you don't want to fail too much or waste too many resources, then save scumming becomes valid or even required. This isn't a little grindy if played on higher difficulties this'd be longest 4 chapter hentai game you'd ever play.