I've approved or rejected a whole bunch of book and newsmagazine covers over the years, and it never ceases to amaze me the sheer variety of opinions that can be expressed over any one cover design. Just now I brought around to several colleagues two possible covers for a book to be published next year.
The book will sell in bookstores, so the cover needs to be catchy, it needs to convey a cogent story about the content, and it needs to pass several other marketing-oriented criteria such as placement of the author's name. The color palette used on a cover is typically also used for the interior, so the cover shouldn't be too monochromatic. Otherwise we wouldn't have the flexibility we need to vary colors in headings, sidebars, and other features. So anyway, I bring these two options around to some peeps for their opinion. (I had a third option but I had already rejected it. Looked too much like tennis balls on a Scrabble board.)
Sure enough, as I knew it would come to pass, some people absolutely hated Cover 1, while others absolutely preferred it. Some hated the title font on Cover 2, some found it really interesting. Some really liked the puzzle-like image on Cover 2, some had a clear aversion to it.
That's why I love covers, there isn't any one right answer.
Design lies very much within each person's emotional center, I think. With writing, we can read a variety of authors and like them all even though their style can vary quite a bit. Sure, there are some authors we just can't stand, but on the whole we can read and enjoy a wide variety of writing styles and never give them a second thought.
But with art and design, our response is more emotional, more instinctual, more gutteral. We react to every design. We have to, there's no way around it. The trouble is, for us decision makers in publishing, we have to choose just one design. Oh, ugh.
When I show a cover around, I'm not just gathering opinions. I'm also gauging those opinions in light of the kind of person I know you to be. For instance, I showed the cover to someone who tends to think on a highly detailed level. Many of the book's intended purchasers also think that way, so I considered the opinion in light of that. Another person was more artistic, so I considered the opinion in that light. I certainly weighed the author's own choice as well.
In the end I chose the version I think will do the best job for this particular book. Will everyone be happy? Heavens, no. But we'll have a book with a great cover that fits the need for a product of this type in the market it's intended for.
Happy happy joy joy!