Eberron *could* be great, but it has ADD
There's just too much in it. I'm not talking about too much fluff vs. crunch - fluff is great - I love fluff. But, it's all this fluff that is supposed to interrelate and just doesn't. It's all over the place. It's as if a marketing committee asked a bunch of folks "in their target demographic" (whatever that may be now) what things they thought were cool. Harry Potter? Check. Steampunk? Check. Indiana Jones? Check. Shannara? Check. Cthulhu? Check. Great! Let's stitch it all together! Sadly, you can't really effectively just run the Indiana Jones portions without running some of the steampunk and noir, as well. I've tried my best to homebrew it enough to make it playable, but every time I buy a new adventure/supplement, I kick myself and think that I could have paid $10-30 for something I would actually use more than once before wincing.
It looks like WotC has devoted a serious amount of resources to getting Eberron off the ground, so I'll just keep my fingers crossed and hope that the focus of it gels a bit as we get underway.
Let me also add the caveat that I think Keith Baker is a great designer, and based on his frequent board postings a heck of a guy, too. I have a feeling - and this is just a gut feeling - that he may have had something really cool originally, and too many cooks just spoiled the pot.