completely disagree. I spent six years in the field of science. For many years, the most glittery, eye-catching, out-of-this-world hypotheses were the ones that got funding. I saw so many of my colleagues come out of undergraduate education and spend four or five years in the wilderness chasing after projects that went nowhere and in hindsight were horrible, though imaginative ideas. Execution is tough, because it's beholden to standards, and thus far more valuable than imagination. Ultimately you cannot properly edit out bad ideas without experiential knowledge. The catch is, go too far, and your knowledge creates prejudices that cloud your vision and block the genius ideas.
Imagination is important. But most of us are born with the inherent capacity to dream; a dreamer is a dime a dozen. Execution matters more. That's hard to find.