It could just as easily mean all of them are very appealing. I know that I would have voted for nearly all of them.
Again, though, this isn't exactly a vote for Dark Sun then is it? "Hey, it's just as popular as any other choice and just as appealing." doesn't really sell the notion.
Look, I know you folks want to paint me as the bad guy here for being a negative Nellie. Fair enough. To be honest, I'd personally LOVE a WotC Dark Sun treatment - say a level 4-20 adventure path that introduces the setting, brings a strong story and includes defiling and psionic rules plus all the really groovy Dark Sun beasties. I'd buy it in a minute. Very cool.
But, my personal preference doesn't really matter does it? Neither does yours. "I want it" is not a particularly good argument. The point I'm making here is, psionics have never been very popular and are not really seen at that many tables. Dark Sun is cool but, it's also pretty niche and lacks a strong, broad appeal, plus, it's been out of print (more or less, saving the 4e foray into it) for longer than the majority of gamers have been alive. It's not exactly high on the list of things folks are aware of.
Yes, yes, I know YOU know about it. But, you're an En Worlder who's either reading this or posting. Both of which pretty much place you outside of the mainstream.
Now, as evidence for psionics not being particularly popular, I presented this thread, which, instead of asking leading questions or being predicated on future actions, is simply asking about past experiences. It's still self selecting and frankly, since I'm polling En Worlders, not strongly idicative of anything. However, I would also point out that in 50 years, psionics have never strongly featured in the game. There are no module series (that I can think of) that leaned on psionics. Even Dark Sun, where psionics has its strongest place, makes psionics a side element and certainly not central to the themes of the setting. And, outside of the small niche of people who actually have played/read Dark Sun, psionics is largely absent. Oh, sure, it pokes its head up here or there, but, it's never really been a big element of D&D.
Which is what this poll shows.
Like I said above, I'd LOVE a big, beautiful Dark Sun book. I think it'd be FANTASTIC. But, I also am very much not getting my hopes up that a setting that's almost as popular as other settings, featuring psionic rules that, in the history of the game, have never really had much of an impact, is going to see the light of day.