Wait for a couple of years for the apps to be developed.
But current Tablet PCs do so much already! With the kick of "Apple's doing one" we've got some innovation finally, they'll get as cool as the Apple one but be a fully fledged multitasking OS to boot.
Firstly, what is to stop you from using a stylus?
Somewhere to keep it!
What is stopping application developers from creating apps that allow annotation of PDF files or that duplicate the functionality of "One Note". If the market demands such functionality, will the market not deliver it?
As you said, they will but it will take time.
Furthermore, what makes you think that software such as "One Note" is anything but a niche market for certain professionals? And do you really need to be able to scribble ugly handwriting on the screen? Aren't there better ways of inputting text? I suppose the market will decide.
I agree, a decent touch on-screen keyboard is a good idea that should be used on other systems. The correction is really good too. It is faster than using a pen, but with the auto-completing browsers and search by keying one or two characters will be just as quick with the pen. Don't forget that doing sketches, diagrams and mixing writing with text (think notes, maths work) is a very useful part of the pen's function.
Anyways, my opinion is that this is an embryonic platform. Once HTML5 starts to take over, the Flash issue will be less of a concern. And with HTML5, you will be able to do things with a browser that you probably couldn't imagine.
HTML 5 based apps, and therefore cross platform, would be a really good launchpad. But with the Apple iStore interface behind their core product lines now i can see plenty of iPhone OS-only based apps.
Will it flop? Not completely, there is a market. But this doesn't innovate, it's not the magical grand leap forwards they want us to believe and it won't be massively popular. It will sell well, but it's not going to be a major line.