I think the amount of praise Draconomicon is getting is well deserved, but I'm also one of those that was a little let down by it. My main gripe was there was too much focus on the "main" dragons (metallic and chromatic) with nothing much on other types of dragons. I really would have liked to have seen some incorporation of, FREX, Oriental dragons, some of the other types of dragons (shadow, mist, deep, etc) and gem dragons. I always thought the primary dragons to be pretty well fleshed out, but the less mainstream ones could have used a bit more, if for no other reason than as an incentive to use them in-game.
As for LM, I wasn't overwhelmed by it either, but then I see it as being more utilitarian than anything.
Damon.