Original is meaningless. There's no point to being "original", really. WoTC, apparently having someone bright running this search for a new campaign setting, has locked in on one of the fascinating traits human beings possess.
I've studied Psychology, and my father is a Psychologist. One of the many interesting things about human beings is how they like "different" things. Humans are used to a certain kind of thing, and they don't want a big change from that thing. However, they like slightly different things from what they're used to.
For example, say a person really likes a certain kind of food. This food is food he's eaten all his life, and while he enjoys it, he's looking for a change. However, he isn't looking for too big of a change. He wants something different, but not too different. This is one reason why varying foods from differing cultures are often found repulsive by people from another culture.
It is simply too different to be liked. Humans do like a slight variation on certain kinds of food, however, and that's why food with the same basic taste is served in so many different ways. Humans enjoy things that are slightly different from what they're used to, but not something that's greatly different.
Humans find large and great changes unsettling, while they enjoy slight changes to what they are used to. This has even been proved to be true from a physical standpoint. Tests were done, and it was found that when Humans put their hands in a pot of water, for five minutes, at a certain temperature.
These people would enjoy the sensation of taking their hand out and putting it in another pot of water that was within 5 degrees of the temperature of the water they had just had their hand in. However, if they put their hand in a pot with a water temperature that was, say, 20 degrees different then what the other pot of water was, they would find it unpleasant.
This was true for many varying temperatures, IE 75-80/70, 25-30/20, and so on. It's just the way the Human mind works.
And that's why WoTC is not looking for a unique, highly original world. They're looking for something that's similar to all the worlds they already have, worlds that people who play D&D are used to and like, but that is slightly different. And that's what will be successful. Same basic food, different way of serving it.
If you don't believe me, look at the three most successful campaign worlds. Notice how popular they all are. Notice how similar they all are, as well. Notice how highly unique and original settings like Dark Sun, Planescape and Spelljammer fared against the slight variations to the old theme.
It may not be fair, but the fact is the unique, highly original campaign world isn't what sells. The slight variations on the previous campaign worlds are.