Have you used it? Does it have a real keyboard? Why is detaching the keyboard a "feature"? Why does a "touch" OS need a track pad? I'm not saying that people who like W8 and want a tablet will not like it, but it's not really a full laptop. Viewed as a laptop, it's one of compromises.
Nope. I haven't. Everything is pretty subjective at this point.
Metro is a fully touch environment, and Windows 8 already has a pop up keyboard much like iOS. If you want to use the Surface as an iPad style tablet, nothing is stopping you from doing so. Just fold the keyboard behind the screen or take it off, and go read a bunch of Kindle books in bed or something.
BUT
What if you want to write up a document in Office. Make a spreadsheet? Model. Play games? That's what the Windows desktop is for. Pop the keyboard on, use the touchpad, and have a blast doing your thing. You can even use a stylus to write mash notes to yourself if you want.
It's not so much that it's trying to find a happy medium between two different form factors, so much as the OS has two environments you can switch between at will and has the tools to support both. You want a tablet, you've got a tablet. A proper laptop? It does that too.
How well does it work? Well, that's the big question. Is the keyboard comfortable to use? Does having a desktop behind the scenes eat too much battery life, even when you're running in Metro exclusively? It could be great, or it could be an awkward mess that doesn't leverage the strengths of either platform. We don't know, and we won't know until it's released sometime early next year.
But I do see the potential of it. Done right, it could be an excellent, incredibly flexible little machine. For me, it's not the concept so much as the execution that's the biggest question here.