But is it a computer?
Take a look at these press shots: http://www.microsoft.com/surface/en/us/default.aspx
While it may look like a handy tablet that's able to convert into a thin and light laptop computer through the use of one of their keyboard covers, it's not by any means. A kickstand doesn't rest on someone's thighs with any acceptable measure of stability. So what does that make the Surface then if it's not a notebook computer, a desktop? Okay, let's run with that. Prop this thing on your desk with this case maneuver every time you'd want to use it as a desktop computer. Is a 10.7 inch display really acceptable when you're sitting at a desk and farther away from the display than you would be if it were on your lap? I don't know about you, but this seems like a nonstarter for anything but a Metro app. Would anyone want to use either one of those keyboards? Microsoft hasn't even made any mention of their size. Are they full-sized keyboards like the one found on the 11.6" MacBook Air, or is it scaled down like those finger-hating netbook keyboards?
This is the crux of the problem with the Surface: it's a mediocre computer, and a mediocre tablet. Microsoft should have shot for making a great tablet, or a great notebook. I'm taking the liberty of calling it a mediocre tablet based on the heft and size of the thing. You mention 16:9 being on every laptop in the market, which is fine, since nobody turns their laptop on their side and views anything in portrait mode like they do on a tablet. 16:9 tablets in portrait look insanely tall.
Also, by having two different architectures, consumers will run into the problem of not being able to run apps that work on the Surface for Microsoft Windows 8 on Intel on their Surface for Microsoft Windows RT (these names roll off the tongue, for people who browse HN and Reddit I'm sure we can handle it, but someone like my sister, girlfriend, dad? Not a chance).
Why no pricing or availability? By announcing something 4-5 months in advance, Microsoft risks the public forgetting and/or not caring about Surface tablet when it's actually released. It has a vaporware vibe to it when there isn't a hard release date or window. Say what you will about Apple but when they announce a new product, they almost always give it price and release date so you can actually walk into a store and buy their product. Microsoft isn't showing a lot of confidence by saying it will be priced competitively with other tablets and having no availability.
I'm still not sure if it includes cooling fans, if it's just a vent then that's a non-issue.
You're right about Microsoft's mantra, but that was before they made their own hardware. When they just licensed software, they wanted Windows everywhere. On your desktop, notebook, smartphone, kiosk, etc. Now that they're in the computer hardware game, they need to sell these Surface tablets at a profit (obviously), and I don't see them doing that when the Surface doesn't excel at any one function as well as a full-blown desktop computer or an iPad.
One last thing, Microsoft making PC hardware puts their OEM partners in a really awkward position. Think of it, they have to pay Microsoft a license fee to run Windows on their hardware in order to compete with Microsoft? That blows my mind, I can only guess some of these partners will move to Android which is (kind of) free.