For my part, in the end it doesn't matter to me-as-DM whether they finish the adventure in two sessions or thirty...with one exception, that being if I'm running multiple potentially-interacting parties side-along and I have to worry about lining them up in game time, a slow group can cause headaches. (as can a particularly efficient group)
That is a tough thing to accomplish and make it not seemed force. (Ever see the ending of Game of Thrones?

) If you pull it off, more power to you. Great work.
Most dungeons are, in one way or another, part of a larger story. An analogy is that a single game is part of a sports team's season, if each game was of an uncertain length and perhaps involving different elements. While the team is playing a game it is, in theory, focused on the game at hand; and only afterwards pays attention to how the game affected their place in the standings and-or their season.
I hear you. I thought when you said it
is the styory, you meant that's what you were doing - a dungeon crawl for a campaign.
* - in the game I play in we had an adventure once that consisted pretty much of just trying to travel through a mountain pass and clear out some dangers. Something like 8 sessions, three PC deaths, and a whole lot of blood-and-guts later we finally made it, only to realize we'd rather missed what we were there for and had to go back. A few more sessions later we'd figured it out, helped immensely by having already dealt with 95% of the risk. Which makes me think - I've no idea now, five years later, what if anything that adventure had to do with any ongoing story; and I'm fine with that. What I remember more clearly (and a bit fondly, even though my PCs spent the trip getting whaled on!) are some key elements and events that happened in the adventure.
I have had games like this too. Memory is a powerful tool. I do find it more memorable when there is a story attached. And the weaker the story, the weaker the meaning of all the trials of the adventure. But, that's just me (and probably just me at this stage of my gaming life).
There is something in your quote, the bolded part, that has always made me wonder; like since I was 15 and playing wonder. With combats so often or long (a recent thread btw), when players forget their actual objective, why doesn't the DM recognize that as the litmus test for a problem in the story? If someone is in a campaign and they have no idea why they are at a specific place or why they are killing something, that seems like there is a storytelling issue. I mean, I love a good fight scene as much as the next person, but I wouldn't only read the fight scenes out of a book. I need to know the characters motives. (Again, just for a campaign, not a solo one-shot.)
IME the trick is to have more than one in the hopper, and drop hooks for several. Then, if for some reason one story falters, the groundwork's already been done for a few others.
Sounds good. If it works for you -

!
It can feel that way, and I'm guilty of this too.
Comes from having too many ideas and not enough nights in the week to play them all out, I guess.
I feel you. Too many ideas sounds great, but man can it become overwhelming.
Published individual adventures may or may not have anything to do with a story arc, or may help it, or may hinder it. One example is an adventure-path-like series I embedded into my current campaign. Was going to be five adventures but a sixth got tacked on; the first, second, fourth and sixth were homebrew modules, the third and fifth were published TSR-era classics that just happened to really fit well with what I had in mind.
Yes, a piece of Saltmarsh was just used by our DM. He uses snippets as well. I'd imagine it's great to do so. Strange that I have always been an all or nothing person; I either create the whole thing from scratch or run a premade adventure. I ran part of Hoard not too long ago. It was for people who had never played D&D before. They enjoyed it. Then I let one of the players take over. That tanked really quickly - partly because they never did their homework.
