This.

If things weren't Quest-locked, then it would be almost impossible to explore without breaking a quest... any quest. Then I can only imagine the level of butt-hurt crying about how only five quests in the game can be completed...

The way it is now is clean, orderly, and saves the continuity of most every Quest-line in the game. Having places and items quest-locked is not only necessary, but is also beautifully done in The Elder Scrolls series.

...but Bethesda is not preventing us from going to McDonald's.

Indeed.
And on that basis maybe the OP should go to McDonalds instead and regain some perspective.

Actually, quest-locked dungeons are not necessary; rather, what's necessary is that they design the quests so that they don't break if you explore a related interior and/or pick up a related item therein. Do that, and you remove the complaints of both groups at once since neither situation occurs.

There's already a partial example of this in the game: inside the final zone of Hag's End (that has the same name) is a false wall that is tied to a Dark Brotherhood quest. You can go there any time you want, since the location itself isn't quest-locked, however the chain for the false wall only appears if you're doing the aforementioned DB quest. Granted the 'magically concealed trigger' is a rather tired device, but it's a lot less invasive than having the entire interior arbitrarily sealed off.

Alternatively, have the quest-related portion of a given ruin be separate from the rest. Labyrinthian already does this with a side-chamber near the main door, however it has the problem that the seal is on the inner door rather than the outer one, which leaves only a small and seemingly pointless (as it's empty save for a couple of 'junk' items) vestibule accessible. In fact, you won't know said door is quest-related until you're actually on said quest, which is a bit obscure in its own right, since it gives the standard 'sealed from the other side' message that implies it's an alternative exit from the main dungeon. Which it isn't, since they're not physically connected in any way.

They could also borrow a page from the way player houses work: have quest items/NPCs start initially disabled, and then enable then when the relevant stage of the related quest is activated. That way it's literally impossible to break the quest, since the thing that would cause said breakage only exists for a given character when needed.

Oh, one other thing: DO NOT have quest stage advancement tied to body count, unless you're going to provide all the relevant bodies when necessary. The CW fort sieges do this more or less correctly, but a certain quest in Riften definitely does not, which causes unnecessary glitches and headaches.

But the falmer statue, Irkngrand, don't have to be locked up! It's just a statue and it's just a dwmeer ruin! They are exactly what they are, awesome, but for everyone.
You would'nt see it and go, Oh look, a giant falmer statue, I know, I'll rip it's eyes out! And if you knew, or saw shiny jewels, just stop them being removable outside the quest.
Just make it so you can't take it's eyes out so you can't break the quest by accident, and admire away.
Make it's eyes removable in the TG quest and leave the place open to all.

It's not like they don't do it elsewere in the game.

Don't hide awesome stuff away, to force people to join guilds to see it or go there.
Which is exactly what they did.

And Snow Veil Sanctum is just a generic ruin, you could always have Karliah appear if you were doing the quest.

The TG don't own these places! it's not like a secret hidden base or something.
The mages don't own Saathal, they're just excavating it, it's owned by the land.

So theres no reason, at all, why you can't go there without the quests.

The Thieves Guild specifically states that they tried to find a way to the Falmer statue in Irkngrand, but were unable to, so Gaius gave up on it.

Saarthal's being excavated by the College of Winterhold. True they don't own it, but they still aren't about to let some unaffiliated person come in and start A) Smashing up the place along with all its valuable artifacts or Stealing said valuable artifacts.

Snow Veil Sanctum is a little bit harder to justify, but Karliah could have sabotaged the entrance so that Mercer (and the Skeleton Key) had to come to get the job done.

The one thing I take away from this thread is to shut up and eat your Big Mac because there's people starving in Africa.

The only part I might agree with is that some other quests require you to get to areas only accessible from other quests. I mean, the Stones of Braenziah would be better if you wouldn't need to collect all of them.

Other than that... well duh, some areas are quest only.
But let us use big words like "ruining immersion" even if that has absolutely nothing to do with all this and how this somehow ruins choices and the like, showing how much you know about how these kinds of games work.
Oh and that sig is [censored] stupid.

So if you’re role playing how would you even know there was a word wall in a locked location or anything for that matter? Reading a website to find out where things are is what destroys immersion. The way I see it, a group got to a location before me and have claimed it for themselves preventing access unless I’m part of that group or I find a way to infiltrate the group. A locked door that I can’t pick just means it’s a special unpickable lock. Of course I’m sure there is no such thing as an unpickable lock, what was I thinking.

I also dislike quest locked dungeons. I looked for a lever for a long time before going to a wiki to find that the sliding wall only is available for the DB quest line.
Not a great mechanism.

I fail to see why this should be a problem. You have no access to it for the time being.
That's entirely reasonable.