I heard this saying and I can't get it out of my head. It came with the fact that if my novels are not gonna be appreciated by my audience, the "great" ideas are not so great after all. So how could I avoid this, beside the beta-readers solution? I am working on an adventure novel which happens in the Middle Ages (the years and the periods of time are not mentioned in the book, though). I'm going to tell you what I know so far about my novel. What worries me if my audience would find this interesting (teenagers and young adults, because the majority of main characters are so, too). And by interesting, I mean if they would stick to the story until the end, or if they wouldn't find it boring. Perhaps that depends on my writing, but I'm still going to tell you my outline. The main plot is about an abduction. A daughter from a royal family is abducted by some fool thieves, but all the evidence my MCs have found led them to another kingdom, so they accused it and started a war. The two kingdoms brought allies from around the globe, making a world war. Of course, the daughter is found shortly after this big mistake, but the war does not end so easily. In the meantime, a scholar girl is studying the most dangerous substance, the mutagenic toxin, which is the reason for why all the monsters exist in the world. To study it, she needs some powerful artifacts (or parts of some device she needs - I don't know what's the best option and which seems little cliche - I'll work on it). Those artifacts, or whatever they are, need to be brought to the girl, so she can combine them and discover the toxin's misteries. In order to get them, the MCs have to travel to different parts of the world, knowing they have to be careful not just about monsters, but the war, too. This was my outline for some time and I'm almost certain I'll stick to it. I can gather other ideas after I begin writing, so I got all figured out for the moment.
I believe all ideas will work. If the prose is strong and the story-telling lucid and engaging, I'll be with you to the end. One time I read a book by Jim Brown on multihull sailboats, because I'm interested in sailing. There can't be anything more boring than reading about sailboats. I wound-up reading all of Jim's books because I enjoyed his writing style. He was heavy on the purple prose, but he did it so poetically it worked. Write your story, then spend some time strengthening the writing.
It's not the idea, It's how you develop it and present it. Some ideas will be out of your reach until you find a good way to write them. That's partly a matter of experience, and partly a matter of developing your vision and voice.
3rd-ing. I've read plenty of books with extremely similar premises; some I love, some are just okay and others I can't even finish. It's all in the execution.
Well that is something to see first thing in the morning. I think in one version of reality Slayer has has a song Raining Cocks, as well as the album of the same name. So yeah there are some great ideas that just don't transfer well to the page. Just cause it sounds good, doesn't mean it will be good for a story. Though I am sure there are plenty of stories that exist on great concepts that just don't come off as all that great in delivery. Though I am sure the two above me would write the Phrase: How dare you bump me in the ass with a mushroom.
It's probably not just in the execution, if you can't get an agent to even open your book because he doesn't find your idea appealing. What else can you do but write what you are enthusiastic about to the best of your ability and hope?
I've seen a 3 minute clip in the movie Up that hit more emotional strings than nearly any other Pixar movie. I saw a 30 minute episode of Breaking Bad where they dropped all the intrigue, story, and I followed Walter White as he tried to catch a fly. Guess I'm 4thing the execution camp. Great ideas should be a multiplier to great execution, not the draw to your product.
I'm 5th for execution. There's really no way for us to say that readers will or won't find it interesting enough to stick with, since you could have a fantastic idea and then use the word 'that' twice in every sentence and, well, that's going to be something that gets annoying. see what I did there? Almost anything can be interesting under the right circumstances.