I think the judging process favors books with depth. A book that excites you on the first read, can show up less favorably by the third read. By that time, the unique newness of the book has worn off and you will see the flaws. The winning books are read repeatedly through the process, so I think a book that wins will give the reader something different on successive reads. . .that translates to depth. I also think it usually favors character-driven fiction for the upper reaches of the age range.
In the committee's discussion rounds, only new things can be said each time. Plot is only one element and kid appeal is only one element. Because members have to keep saying
new things about the book, the book has to stand up against books that do several elements superbly. Once you've said how good the plot is or how much kids will like it, you've got to find more to keep talking about. Kids and adults love plot, especially when they are reading for pleasure. But character, theme, setting, and description will also be looked very carefully. I think a plot-driven book can win, but it'll have to be very strong in those other elements--and that's not always the goal of a plot-driven book.
As a former teacher, I understand completely that it would wonderful if we could make kids excited about reading at the same we're giving them books of top literary quality. Sometimes we CAN find books that do both--and

when it happens!!! Other times we have to make value judgements about which criteria matters more to us that year, that class, depending on the readers we have before us. That doesn't make either of those criteria unimportant to literature as a whole, though.
In this discussion, we are thinking mostly about what we would
gain if mass kid appeal were made more important than other parts of the criteria (I say "mass" because there ARE children who loved every book that's been deemed unpopular in that article). But I think we would also LOSE something of value to us as writers.
The Newbery Award and the Printz are one reason publishers are willing to take a chance on books that don't immediately shine in P&L statements. Many of us already feel there is a very slim place in the publishing world for "quieter" books and multi-cultural books and books that are unusual or that are in genres that are not as financially successful. The Newbery Awards (and the Printz, etc) are definitely one thing that holds that place open at all. If I look at the other thread about which books people would like to see win. . .I'm not seeing very many books I would consider to have mass appeal to children. THE HUNGER GAMES is the only one that jumps out at me. And yet, elementary school teachers are probably not going to be able to teach that one without some hesitation over the violence factor.
I honestly don't think we can have it all under one award. I challenge you to find that book this year that you think covers everything we have deemed important here:
The majority of elementary and middle school teachers can teach it and will enjoy teaching it.
It makes a wonderful gift that grandma can hand off to a child she doesn't know very well.
It is among the highest literary quality that's published this year.
It will have broad kid appeal.
And my own addition: It will continue to encourage publishers to occasionally take a risk.
I think HOLES accomplishes all that, but that book doesn't come along very often.
Books with kid appeal are honored in *several* other awards (the Quills, the Cybils, the state kids' choice awards). Those awards don't have the same history and prestige yet of the Newbery, but I would say those books
do get rewarded in other ways (namely, book sales). Maybe as teachers we should make more use of those award lists as our general classroom reads.
On a personal level, in the world beyond our children's book circle, I haven't found that the general public sees gold and silver seals that differently. Susan handles the harder parts of winning the medal with superhuman grace and humor, but I've joked with her that I think Kirby, Jenni, and I actually got the better deal.