"Allowing for options" is different from putting in a silly mechanic and then leaving it to players to restrict themselves from using it. It's the developer's job to give you a fully tuned game, not a toolkit for you to pick which mechanics you like and ignore the rest.
I'm sorry, no. I cannot agree to this, nor can I explain how any rational thinking person can agree with this. Chekov's Gun does
not apply to game design.
You adhere to the concept that every game should be "fully tuned" and "not a toolkit". If anything, this reveals that you have no imagination and/or expect way too much of game developers. You're stuck in the thought that it's the developer's job to create a game and dictate how the player plays the game.
No. That's not how it works. The developer can (at best) create a game and
expect how a player will play it. The dev has no control over how players play his games, and the one that tries only betrays his own imagination.
If a game has a range of "mechanics" that serve specific functions and are balanced against one another that work together to make the game fun, then that's great, dev did a good job... until the inevitable happens when someone introduces the metagame, usually by asking what happens when one of the mechanics is removed/not used (another common scenario is asking what happens when a new mechanic is introduced, but that's beside the argument here). Do the rest of the mechanics stop being balanced as a result? Does the game fall apart at the seams because of its absence? If so, then the dev did not do as good a job as expected, because he didn't account for the metagame, or chose to ignore it. That's his problem, but it should not become the player's problem.
The magic of Thief is that players
can pretend the blackjack doesn't exist and the game doesn't care, it just carries on and so does the player. I don't have an exact playbook for Thief here describing every move needed to beat it, but I do know that you don't need even half of the gear (or "mechanics" in your words) the game has to offer to win. They're just tools in a toolkit, to help get the job done. Thief is in a very small group of games that are designed so loosely in terms of mechanics, yet works as a result.
I would continue building my argument to counter yours, except you've already destroyed your own argument. What I do mean?
I've ghosted The Dark Project and I loved it, but you can't get mad at people for criticising a game for things that are in the game, nor can you get mad at people for not using your LARP mode where you pretend the weak aspects of the game just magically don't exist.
Point to me where The Dark Project introduces ghosting as a mechanic. Point to me where the game intends for you to use it. I'll skip ahead: It doesn't. At no point does The Dark Project mandate ghosting. ("Undercover" doesn't count because you're masquerading as a Hammerite, not ghosting. You're free to blow your cover at any point.)
In addition, ghosting requires that many of your so-called "mechanics" simply not be used. That breaks your (stupid) argument that if a mechanic is introduced, then it's to be used. In fact, the entire concept of ghosting is a fan-made term to describe a certain method of playing the game. And here you are, admitting to having played the entire game like that, pretending that aspects of the game magically don't exist. Now who's in pretend LARP mode?
Where are the limits on your "just ignore it" logic?
The limits are restricted only by the will of the player (a.k.a. the metagame) and the outermost boundaries of the game, i.e. whether the game becomes completely unplayable as a result.
While we're at it, explain the Armageddon spell in the Ultima games. The devs put it in the game and told you how to use it, therefore it's there to be used. But what happens if you do?
What's the comparison to the blackjack?
To paraphrase yourself: "It ruins the game." But unlike your exaggerated words, the Armageddon spell
literally ruins the game, to the point of no return. That's its only purpose, by design. According to your seemingly ineffable stance on video game design, the Armageddon spell should not be in a game... but it is. Several of them, in fact. And they are considered to be great games, milestones in gaming history even. And the inclusion of the Armageddon spell is one of the notable parts of their game design.