No live view preview that I can see unfortunately, though as it does support video viewing from the 5D2 now I wouldn't be at all surprised to see it make its way into a release down the line. The interface is very dumbed down. It doesn't even let you change camera settings from the interface, despite showing you them. It's pretty much a floaty bar that lets you set meta data and any develop presets on import, and a big shutter button.
I'm interested to see if they provide support for the big digital MF manufacturers, with Phase and Hassleblad both having their own RAW/thethering software they're trying to push. It would be nice to eliminate another program from the workflow but I doubt we'll see it anytime soon. I'd happily be wrong though!
Softproofing would be nice but I never print anything straight from Lightroom. If i'm taking the time to properly softproof it likely means I've put some time into editing it, which I'l have done in PS anyway.