To be fair, several of your complaints are really polish. This isn't the RTM by any stretch, and from what I understand, the reason for even having the consumer preview is to get feedback like that. Saying it's doomed because of some of these things isn't really fair.
I'm not sure about the mouse-tablet thing, in general, sure. But the specific way you use the lock screen, for example, is likely to get fixed before they release.
(I've been using the Consumer Preview for about a week on my primary machine and I'm pretty happy with it.)
The problem isn't any specific thing. Rather it's the fact that Microsoft is (once again) trying to make a single UI fit both the desktop and tablet use cases. It makes no sense. It's like trying to fit the same set of controls onto a car and a motorcycle.
All of these specific UI issues result from this impedance mismatch between tablet and desktop UIs. So yes, Microsoft may iron out the specific bugs we bring up. It won't matter, though, because UI issues of this nature will crop up at every seam between the desktop and tablet interfaces. What will happen is that Microsoft will patch these piecemeal and we'll end up with layers and layers of band-aids trying to compensate for a fundamentally broken design.
I don’t want to say it’s doomed. Most of the people at Microsoft who decided to go that way are likely cleverer than me. I can only say that I don’t see their plan and I’m not sure whether they can be successful. (And also that I personally don’t like Windows 8 all that much, but that doesn’t say much.)