What Could Have Been

This was going to be his final concert tour. And then he died.

"For of all sad words of tongue or pen,
The saddest are these: 'It might have been!'"

—John Greenleaf Whittier, "Maud Muller"

This is when directors or writers release details about plots, characters, back stories, or other elements they thought about adding to the story at one point but ultimately never did. Unlike All There in the Manual, however, this new information is not released as Word of God with the intention of being added to the Canon. These elements are only What Could Have Been but never were and never will be part of the story proper.

Some may quickly find a home in Fan Work. Many fans love hearing the possible paths their favorite story could have taken... even while breathing a sigh of relief (or feeling disappointed) that they ultimately didn't come to be.

This can also refer to a Sequel Hook that never got a payoff, alternate casts or directors, or even tantalizing news that the entire story was completely different from the one we all know, when it was first conceived.

Just a few typical reasons for why stories get altered along the way:

The Media Watchdogs or executives said, "No," or at the very least, "Yes, but only if you change this."
Technical reasons: The people who were originally hired to do it backed out, the special effects plans didn't play out in their favor, there was not enough money in the budget to include it.
Writing Around Trademarks—They couldn't get rights to it.
Story quality—The writers simply decided on something different instead because some ideas, no matter how cool they sound when they first come to you, just have to go (or, in the case of comedies, the joke wasn't as funny as it should have been). Maybe the author realizes the fans wouldn't be too happy about seeing the death of a sympathetic or popular character you originally planned to kill off (not that it stops a few people). Or maybe you realize what sounds oh so cool in your head pushes Willing Suspension of Disbelief too far on film or paper. Or maybe it was a bad idea to begin with. In any case, someone eventually had a better idea.
A side effect of Throw It In—Something had to be thrown out in its place. (This apparently happens a lot when you're working with Harrison Ford.)
The creator/actor/voice actor/author/director dies. Or suffers loss of reputation. Or goes bankrupt.
Time constraints: Sometimes the creators simply run out of time and are unable to implement it.

A good place to find What Could Have Been is in DVD Commentary and out-of-continuity pilots used to pitch a show.

See also The Other Marty, Vaporware, Development Hell, Dummied Out and Mid-Development Genre Shift. Contrast with Offscreen Moment of Awesome where a particularly grand moment is seemingly perfectly set up to happen but then isn't seen, and They Wasted a Perfectly Good Plot for when they used an awesome idea in a horrible, horrible way. Occasionally something that was removed survives in another part of the series, then it is Refitted for Sequel.

For further reading, see the TV Moments That Never Happened thread at Television Without Pity, the Original Vid Junkie's "Never Got Made" files, and the "Movies that Never Were" series at CHUD.com, the links for all of which are included in this lost movies entry. This subject has also been covered by The Onion A.V. Club here and here, and at OMGHorror.com here.

Examples of What Could Have Been are listed on these subpages: