The talk of "unusual" campaign settings points at DS more than DL, so that keeps DS in the running, I think. I'm nervous about 4e's ability to combine "unusual" with "all-inclusive;" the two ideas are hard to reconcile, and while you can do pallette-swaps and "mechanics are a skeleton to hang any race on" work-arounds, there's a limit. Eladrin, for instance, might be able to keep the raw mechanics (though teleport is weird), but the idea of an arcane-magical archfey from a verdant parallel universe kind of ruins the "sand in your jockstrap, sweat in your eyes, knuckles bloody, lips shriveled" atmosphere in DS, so they wouldn't be able to keep much else -- they'd be too different from "core" eladrin to be able to use "generic eladrin feat #328 from the Complete Faerie" for instance, and part of the all-inclusive 4e philosophy has been that nothing published excludes anything else published. I'm not convinced there's not a solid work-around WotC can figure out -- or a not-so-solid one they'll go with anyway -- but it's riskier.
Speaking of risk...
Mercurius said:
Dragonlance = bad financial choice.
Dark Sun = good financial choice.
I'm guessing WotC opts for the latter.
Why do you think that? In my mind, it seems you have it entirely backwards. Dragonlance has several editions' worth of sales history, a very successful third party run, and, above all, an already-successful novel line that is celebrating a fortuitous anniversary. Dark Sun may have been good back in the '90s, but it's been more than 10 years since anything new has been made and marketed under that brand, and the last time it was tried, it wasn't exactly a resounding success, in part due to an inclusive philosophy ("PALADINS?! IN DARK SUN?!"). When it was successful, the market and the game were in very different places, so replicating that success would be a gamble. The built-in fan base is smaller, and the weirdness of the world means it's going to turn off more "traditional D&D" fans.
Dark Sun is a setting you do like a movie studio does a promising indie flick, I'd think: You do it when you're sitting on top of the world with successes and can do what you please, knowing that you can have a mild success or a break-even point and be OK. You do it when you can afford to take a risk (or when you can't afford NOT to!), not when you're looking for a sure thing.
Maybe WotC is able to take that risk in 2010 with the setting book (or perhaps they can't not take the risk). DS would be a very hedged bet to take, given the amount of fan buzz on the thing, so it would make sense.
But DL is a sure bet in comparison. And given the specific publishing industry troubles and the general economic troubles, the "safe bet" would seem more likely to me.
DS is a very real possibility, and I'll be pleasantly amused if they choose it (and very cautious about what it will be...Eberron succeeded only because it was already assuming a lot of the same things 4e was, and FR was hosed even though it wasn't as hostile to those things as DS might be). DL also seems to be a very real possibility, and that seems more like the safe bet.
On the bright side, 4e DL might be the first DL I check out, given that I've never been into the novels enough to get into the setting before, but I've heard enough good juju about it that I figure there's something there.
