Writers are not the goose that laid the golden eggs.
Even if they were, the goose still has to take a shit at some point, and it’s important to know the difference between a shiny metal ovum and brown, corn-speckled mush. If writers roll with every idea they squeeze into the nest, they’re bound to have several turds show up in their bibliography.
See, an idea is not a story. An idea is just the beginning, and the writer surrounds it with plot and character until there’s something worth writing. Or better yet, until there’s something worth reading. Samurai in space is a cool idea, but it was turning them into Jedi Knights surrounded by cool heroes and fun villains that made Star Wars great. (Well, the original trilogy, anyway.)
Many ideas sound great on paper, but they can’t all be built up into a story. I’m contracted to write a novella, and I had what I thought was a pretty solid idea. However, by the time I plotted it all out, I realized I had no clear protagonist and no likable characters. Good conflict and a decent plot? Sure. But that doesn’t matter if the reader doesn’t give a shit about the characters.
I stripped it all back down and came to realize that this idea just doesn’t work in this format. Sure, I could punch it through and hope compelling narrative sucks in the readers, but what’s the point of that? It’s like saying “Meh, I’ll settle for three stars from reviewers.” That doesn’t do anybody any favors.
If a writer finds himself with one of these ideas, it’s time to stash it away until the alchemy in his brain can catch up and do its thing. There may be a place for it later, but if it’s not ready now, suck it up and move on to the next idea. A writer shouldn’t fling crap at his editor, and more importantly, he shouldn’t fling crap at his readers.