Did not take the time to look at this but can developers use the Direct X 11.2 API with metro applications?

It's garbage.  The demise of the desktop PC is incredibly exaggerated.   Laptops stand to reason to be next item to disappear.   If you want the most power, speed it's still contained within a desktop.   Windows 8 is an abortion of an OS.   It falls in the long line of mid-tier garbage OS's between the quality ones

95- 98 - Win ME- XP - Vista - 7 - Win 8 - ???.

It's an OS built around tablets and cellphones with little thought of it's overall implementation.    

Why would they need to concentrate on it when there are better ways to incorperate it(which they had for years already, just sitting there) other than slapping a tablet/smartphone UI on a desktop OS and call it a new version which people don't use in the same way, not to mention I avoid the touch screen on my laptop because it leaves a lot of finger smears that I have to clean all the time.

Windows 8 UI doesn't work on desktops, I use it. Yes, there are learning curves. Yes, the interface has a huge disconnect and are like seperate things slapped together. It doesn't work.

If they want then I don't see why not, it's just a library call.

I hope xboxone developers make good use of it. I wonder how much of a difference will it make

No it is not that simple, you can do/call whatever you want within the Metro UI sandbox/VM and this why I was asking.

Anyway I got my answer from the build conference.

As far as I know, DX11 is already being used by the UI, so 11.2 would just be an extension to it.

I disagree.  The changes made to the OS aren't just for the benefit of tablets or mobile phones.  The changes to the task manager, to Windows Explorer, offer no benefit to mobile devices. 

I don't disagree that as a UI the Windows 8 desktop has a functional disconnect between the Metro UI and the Explorer UI, nor will I argue that Microsoft doesn't have a long way to go before that chasm is bridged.  But I disagree that Windows 8 is necessarily slow.  Does Windows 8 require relearning, absolutely.  I have been using the Explorer UI since Windows 95 was in beta.  I helped mold that UI over the years into what it has eventually become.  So, yes I'm fully aware of the challenge the Metro UI creates and the relearning it forces upon users.  However, once uderstood, Windows 8 doesn't represent a significant challenge for users.  The problem is that the UI has changed and that users want backward compatibility in the UI.  Not that the UI nor the operating system doesn't work.

That being said, there was nothing significantly wrong with Windows Vista.  The problem with Windows Vista had to do with the memory requirements, memory requirements which didn't change with Windows 7.  The only thing that changed between Windows Vista and Windows 8 is the fact that memory became cheaper and more plentiful, Windows device drivers became updated for the new driver model, and hardware performance increased.  To emphasize this, the Aero Ui of Windows Vista went from being a component of Windows Vista Ultimate to a standard component in Windows 7.  The reason it wasn't a standard component was because of the limitations of both memory and GPU capabilities at the time.  Capabilities which somehow disappeared between the time that Windows Vista and Windows 7 were released.

The major problem with Windows Vista beside the failure of the technology meet the needs of the OS was the fact that the OS consumed 100% of the memory.  As I've stated elsewhere, this was because the original intent was to include a SQL-based file system called WinFS.  Like SQL Server, the OS consumed 100% of memory to ensure the OS had sufficient resources for the file system server.  In turn, the OS would relenquish memory as applications needed it.  This was a fundemental change to what people were used to.  Between Vista and Windows 7 there were few performance differences. 

For people who actually used Windows Vista through SP2, and whose hardware was supported by the OS and worked well with the OS, it worked just as well as Windows 7.  Me, personally, I liked Windows Vista better than Windows 7.   Your suggestion that it was the same as Windows ME isn't even an accurate one.

Windows ME was an attempt to bridge the the DOS-based Windows 9x with Windows NT.  It failed because there were fundemental flaws in the OS itself.  It was a consumer ONLY OS.  You couldn't network it, and businesses couldn't license it.  It offered poor support for Windows games and even poorer support for MS-DOS games.  It required those upgrading to buy completely new system utilities.  And the worst part about it was given time, the OS functionaly got worse.  It offered none of the self-repairing benefits of NTFS, it lacked both full forward and backward compatibility, and given the Windows 2000 was released approximately the same time it Windows 2000 Professional represented a better, more stable OS option. 

Windows Vista, by comparision had none of the challenges Windows ME did.  The majority of applications compatible with Windows XP were compatible with Windows Vista.  The majority of hardware intended for Windows XP was compatible with Windows Vista.  Besides anti-virus utilities, which hadn't been backward compatible with prior versions of Windows since Windows 98 or Windows 2000, and older software and hardware designed for previous versions of Windows but still compatible with Windows XP.  With the exception of Nvidia graphic cards, Windows Vista was a solid, stable OS from day one until the release of Windows 7.

Windows 8 doesn't have the same challenges that Windows ME did.  Windows 8 is solid, stable.  Yes, the OS requires users to relearn but it works.  To exemplify this fact, Windows ME was Windows 4.9.  There was no version that ever continued the 4.0 kernel.  It was abandoned.  Windows XP was built upon the Windows 2000 (Windows 5.0) kernel, and Windows 7 (Windows 6.1) and 8 (Windows 6.2) are both built upon the Windows Vista (Windows 6.0) kernel.  Even Windows 8.1 (Windows 6.3) is built upon the same kernel.  So, in terms of an OS no, Windows Vista isn't a failure and neither is Windows 8.  Microsoft if anything has double-down with Windows 8.1 and hasn't abandoned any aspect of Windows 8. 

You're forgetting Windows NT and Windows 2000 in that list.

Windows XP on release was essentially a re-skinned Windows 2000, heck even the drivers are interchangable, however that changed after a few service packs.
Plus, Windows XP was problematic for everyone moving off the Win9x ecosystem and onto NT, Drivers, software and games was a big gamble to even get working, but people seem to forget how much of a pain XP was on release because it was around for such a long time.

So in the end...
Windows 95, Windows NT, Windows 98, Windows ME, Windows 2000, Windows XP, Windows Vista, Windows 7, Windows 8.

Windows Vista I didn't highlight because it suffered the *exact* same issues as XP on release, I.E. Slower than the previous OS, limited compatability with older Drivers, software and games, but matured a few years after release.
Heck, nVidia was a cause for something like 30% of the blue-screens Vista got.

Sony doesn't use DX on their consoles, derp.

OT: The sad thing here is MS limiting what PCs can do, oh well :/