It's the way the story is told. If it was all about the idea, you'd just read the Wikipedia plot synopsis, say "ah what a great story that was, so glad I read it" and move on.
Jim Butcher had this argument with a bunch of fellow writers on a writing forum. The argument went back and forth. His side was that it was the execution that mattered. He said that a good writer could tell a successful story based on a terrible premise. It wasn't the idea that mattered, it was how the writer pulled it off.
The argument raged across the forum; idea - execution - idea - execution... until Jim threw down the gauntlet. "Fine. Give me your worst idea. No, give me your two worst ideas for a story, and I'll write one and show you." The forums churned for a bit and the other side came up with what they agreed were the two most hackneyed, clichéd ideas they could think of.
Pokémon, and the Lost Roman Legion.
Jim took those and wrote the Codex Alera series. Point, and New York Times Bestseller list spot: Butcher.
Didn't he already do that same sort of thing with his Dresden Files series? I feel like Jim Butcher only writes books on a bet, based on terrible ideas.
He wrote Dresden Files in a way that his teacher suggested (not with the ideas) to show her how bad her way of writing was. He was wrong.
That's where he learned it was about execution.
The only idea he included, just to kind of rub things in was a "Talking Head" in Bob the Skull. He made a literal talking head that would explain things to Harry, which was a fiction writing "don't" that he purposely violated... to great effect.
She counseled him to take the things he loved--fantasy, and Robert Parker detective novels--and combine them. He had been dead set on making sword-and-sandal high fantasy. He followed her instructions on that, too, and we got Harry Dresden.
It basically tells you the plot on the first page, and yet is 1000 pages of something incredible. It's like being able to see inside someone else's mind - not being told what they're thinking, but being able to feel the emotions as they do.
One thing that's missed is that much of the impact of the writing depends on the reader's capacity to grok it.
Many people read at the superficial level, and the takeaway from a book for them might be equivalent to the spark-notes version. Even between readers who are level matched, there are vast individual differences. Some readers can be aphantasiacs (no ability to visualize) and others - hyperphantasiacs. A person can have vastly different experiences from reading the same text depending on how developed their visualization skills (cognitive versus emotional, visual vs abstract, etc).
The argument raged across the forum; idea - execution - idea - execution... until Jim threw down the gauntlet. "Fine. Give me your worst idea. No, give me your two worst ideas for a story, and I'll write one and show you." The forums churned for a bit and the other side came up with what they agreed were the two most hackneyed, clichéd ideas they could think of.
Pokémon, and the Lost Roman Legion.
Jim took those and wrote the Codex Alera series. Point, and New York Times Bestseller list spot: Butcher.