Remembering Lost just makes me angry. If I ever watch it again, I'll end it when they open that hatch and just assume they unleashed the smoke monster that then killed them all. That's a better ending to anything they could have come up with and at least I won't have to suffer through inane plots, stupid characters who never talk to each other, pointless literature and pop culture references thrown in to make the audience feel clever, and a thousand and one further mysteries thrown in just to keep viewers coming back every week.

With regards to your point above Hansen regarding having a detailed story plan being overrated - I can't say I agree, especially if your story relies on a big mystery or central mythology. Of the 4 shows I'm aware of that have such a mystery at their heart that I've seen, all have failed to deliver on those expectations generated when they began it - X-Files, ALIAS, Lost, and BSG - and we know all of them didn't actually have an answer in place before they started down that road. Furthermore, another initially successful TV show, Heroes, then went completely off the rails because the subsequent seasons, which they hadn't planned for at all, were rushed into production. The record isn't good.

The 'making it up as you go along' can only work if you're really fucking good at writing and/or you know your material really well. The most successful multi-arc series of them, Babylon 5, is masterful in how well connected all the bits are - season 1 is a text-book example of how to lay the groundwork and every season expands and extends beautifully. But not all of it was set in stone, and JMS routinely had to negotiate ways of getting through major obstacles such as actors leaving the show. But then... that was his skill and planning as well, he had written 'trap doors' for all of his characters which allowed him alternative stories should they leave.

I can say with authority based on talking with someone who was on a conference call with ABC execs during that time that up until season 6, the island was supposed to be something very very different than what it was ultimately revealed to be.

Long version: 

There was a conference call with the creators of a show that was in development and set to air on ABC.  I won't reveal names, so let's clear that up right now.  This show had elemnts to it that were in the vein of science fiction and had an  overall mythology that ABC wanted to get in on early.  During the part of the discussion as to the source of this show's shenanigans, an ABC exec (again, no names) was heard by a few people to have said something along the lines of "The only thing it can't be is alien, because Lost's island is going to turn out to be from space."

Oh, there's plenty of good there.  Great performances, good stories, amazing score, and lots of beauty shots of my old home.  The frusration with Lost is largely that it got key things wrong, not that it didn't do enough right.

Now THAT would have been an ending that fans hated. Say what you will about the current ending, but at least it fits into the overall tone and mythology of the show.

I dunno, there was a room full of gears or some shit. Like I said, I didn't watch the show.

And just because they retconned an answer doesn't mean that was the answer they had in mind when they started. Have you learned nothing from DIF?!

I couldn't be bothered with Lost past season 1. Perfect example of a great setup with no-where to go and no plan how to get there.

BSG, for all it's faults towards the end, did a much better job of making it's overall mythology feel cohesive despite making shit up as they went. I know people really dislike some of the choices in the finale, but those elements are introduced and referenced as early as half-way into season 1, and don't feel as much like left-field wtf moments to me.

I still say the more planning the better, this is one reason Game of Thrones has been so successful so far, they have a multi-year lead on where the story is going and are able to see what works and doesn't work and craft their story arcs around that.