Dance Central certainly doesn't seem like a launch title, it's a solid experience.
The body tracking is pretty solid and pretty much everything it missed could have been chalked up to my lack of coordination and dance experience. It's definitely a good work out and far more immersive than Dance Dance Revolution, requiring you to use your whole body instead of just your feet.
Adding DLC to the mix (like Rock Band) could make this title have a high degree of replayability, but at $3 a track it's a touch pricy when compared to the 4-5 instruments across 4+ difficulties you get for 1-2 dollars in Rock Band.
The only downsides are that there is no tour mode and no custom avatars. It'd be nice to be able to create your own Dancer like in Rock Band and I can't really think of a reason that this would have been a tall order. Perhaps there was pressure to have it ready as a launch title that drove Harmonix to keep it simple. In any case, Dance Central is a fairly plain game without any real depth, however it makes up for that in spades with it's solid gameplay.