a) Only the ARM version is running Windows RT. The Intel version I wrote about is using "Windows 8 Pro", which contains the regular Windows desktop.
b) A BT keyboard for the iPad is something you need to select separately, and schlepp around inconveniently. A cover goes together with the device. Stuff like this matters.
As for whether it's doing anything new, dunno. The thing is that with products like this, it's a matter of degrees and refinement - at some point you cross a threshold and a concept works. That's why the iPad works, but Tablet PCs didn't.
The product most similar to the Intel-powered Surfcace + Touch Cover is the Android Transformer Prime with the optional keyboard dock. But the keyboard dock isn't as svelte as the Touch Cover, and Android doesn't have the application base of desktop Windows when used as a laptop replacement. And yet the Prime garnered a lot of interest. Microsoft seems to be in a unique position to offer this refined version of the idea.
Will anyone want it? Time will tell.