What does that have to do with touch on the desktop being commonplace? Sounds to me like you're trolling here Andy.
NT was originally designed for RISC chips and has actually run on more RISC architectures over the years than it has CISC. The idea that it "isn't designed for it" is simply nonsensical.
The first version of Windows NT was designed to run on CICS too so it goes both ways and there goes your point. The fact is that Microsoft dropped support for the ARM architectures long ago. Do you really think they kept ARM in mind when developing future version of Windows? How about the whole Longhorn/Vista debacle? Do you think as they were cramming the woefully late Vista out the door they said to themselves, "Hmmmm... we better build this thing so we can run on ARM again someday..." If that were the case we'd have seen complete ARM implementations of W8 long ago.