I always liked the heightened stakes and sense of danger and realism that comes from not preventing the player from doing stupid things.
The contortions that Lucasarts hade to do to make it impossible to put Monkey Island in an unwinnable state fit right in with a game that is supposed to be absurdist comedy, but it is hard to pull off without changing the tone and reducing immersion, constantly reminding the player that it is all just a game.
I admit that I was working from memory there and it’s been quite a while since I played Wishbringer myself. I’ve also never made an effort to intentionally put it into an unwinnable state, and that would really be a necessary first step to exploring those boundaries.
I guess I should revise that statement downward to say that it’s harder to get Wishbringer into an unwinnable state accidentally than it is for games that Infocom explicitly advertised as “expert-level.”
I’m still undecided on which way I’m going to go in my game as far as the level of preventing and/or notifying about game unwinnability. When you say you like the heightened stakes, do you mean of unwinnability that you as a player may not be aware of, or the stakes where you can kill yourself or lose the game, but you will know about it and start over from a save? I’m eager for opinions here!
It doesn’t prevent you from getting yourself into unwinnable situations, e.g. I think you’re screwed if you disturb the leaves or don’t get the letter from Miss Voss, both of them near the beginning of the game. But at least for some of them it will award you negative points, which is a pretty clear indication that you just screwed up.
Unless you’re playing the Solid Gold version, where the time limits were accidentally removed (almost) 
do you mean of unwinnability that you as a player may not be aware of, or the stakes where you can kill yourself or lose the game
I meant both, but I should probably qualify it a bit. It is important to remember that it is about creating an illusion of danger and high stakes for the player while att the same time avoiding frustration. I probably wouldn’t like a modern game that was quite as cruel as an '80s Infocom game, because my expectations have changed and I save less often.