Except for: "...the boss fight (which is unfair..."?
Yes, which I already conceeded way back at the beginning of this. However, as I have said repeatedly, though I may as well be talking to a brick wall, the boss fight is avoidable. It is not at all necessary to defeat Acererak in order to loot the dungeon and take his stuff. Like I said before, the final fight is also a test, like most of the rest of the dungeon, of whether you blindly blunder into things. It is lethal primarily to the group that tries to solve every problem by achieving surprise and fighting to the death. It's unfair primarily because there are no clues to go on, and none of the means of successfully defeating the demi-lich are the sort of things that would be obvious to an experienced player or which are within the power of a character at this level. This is not true of the rest of the module.
For myself, I find ToH as an interesting adventure concept. It's the Paranoia adventure for D&D.
No it isn't. For example, the 'Through the Looking Glass' modules are Paranoia for D&D. They are hideously lethal, terribly unfair, and get this... somewhat humorous. They also have none of the reputation that ToH, and for good reason. Nothing in the presentation of Tomb of Horrors indicates this is to be a light hearted romp where death is arbitrary. It is clearly intended as a test of player skill.
I see it as intentionally, designed to be unfair.
No, it isn't. It's intentionally designed to be a blow to the pride of any player who on the basis of his character's power thinks himself a highly skilled player.
It's unfairness is the basis for it's reputation as a classic adventure module.
No, it isn't. This is the reason why almost no one has been able to replicate the success of Tomb of Horrors. They don't understand the module at all. If the basis of its reputation was simply its unfairness, not only would it not be the most classic module of the sort - as many older modules are far more unfair - but it would have been easily eclipsed. It's trivially easy to make a trap filled dungeon that is more unfair than Tomb of Horrors. Lots of people tried and lots of people succeeded, and then wondered why no one appreciated their efforts.
Making a hard dugeon is EASY. Making a hard dungeon that is also fair is VERY HARD. That's why Tomb of Horrors maintains its reputation with so many gamers. It's not just nostalgia. It's that there is to this day almost nothing else like it. But, there are tons of grossly unfair modules by lesser authors that didn't understand the magic Gygax had wrought.
It's unfairness is its whole claim to fame. To say it is perfectly fair is to completely undermine its whole purpose.
On the contrary, to call the module unfair is to undermine its whole purpose as a tournament module, as a serious test of player skill, and as a tool by which DM's teach players with big heads that they still have a thing or two to learn.
As a tournament module, I can see how its unfairness might be fun for some.
Does that make the slightest bit of sense? As a contest, you think its unfairness makes it fun? That's gibberish; people don't generally prize contests for their unfairness.
But as a campaign module, it is unfair to the point of being mean spirited.
As a campaign module, it might be reasonable to say that it hard to the point of being mean spirited. As I said right from the start, don't send your players beloved characters that are the result of years of roleplaying and character development into this meat grinder. But get this, being hard does not make something unfair. They are not the same thing, and you've repeatedly tried to conflate the two.
It's one of those things, like Thermonuclear War and Tic Tac Toe -- the only way to win is not to play. There's no real reason for the PCs to go into it -- there are other dungeons to explore.
Even to the extent that that is true, it no more makes ToH unfair than Tic Tac Toe is unfair.
But discussing it in this thread is weird because some hold it up as a great module because it is the toughest, most dangerous, most deadly dungeon of all time, and some others say it is great because actually an experienced party can navigate it with little harm. Aren't these views are mutually exclusive.
No. Why would they be? Are you saying that a fair module can't also be difficult? Because that seems to be the sum of your confusion.
And incidently, it is NOT the toughtest, most dangerous, most deadly dungeon of all time. It may have that reputation, but I'd argue that in most cases that reputation is undeserved and the product of ignorance on the part of those that say it. If you've played through S1, S2, C1, I6, and assorted other super dangerous modules by a DM with the gloves off, and you still think S1 is harder then I can only disagree. But if you think S1 is the toughest, most dangerous, most deadly dungeon of all time, then I'm willing to bet that in most cases ultimately you are just repeating what you've heard and have no real basis of comparison.