As Graphic Designers, it can be argued that ideas are simply the most important factor when it comes to producing a successful project. They're almost as if they were invaluable commodity, one that, when spent and used correctly, can be used to solve a wide variety problems. Exactly what graphic designers are for.
However, these ideas are only ever as good as how they are developed and, not matter how visually interesting or engaging a piece of work is; These ideas must always be presented so that they may be communicated to an audience, and must be appropriately constructed to serve this.
Everyone is capable of ideas, it's "the rule, rather than the exception" in human cognition; but how we develop and apply these ideas is how we, as designers, take ideas from concepts and use them as a platform to communicate with people and, at a high enough level, society.