It's not something done in a desktop OS previously (Apple's implementation of 'touch' in MacOSX was different, though probably better), but not new in terms of tablets. Arguable it's not an improvement on what they've already done, trying to do something differently doesn't necessarily mean it's a good idea. The 'All Apps/Programs' I admin is...pretty poor, how it was previously was definitely better.
There are some positive things I would say, whilst it has a lot of good stuff for tablet interfaces (for me, it's useful in that I sometimes like to remotely access my desktop).
I think some of it integrates well into the desktop OS - perhaps better in 8.1, I prefer how I'm using the icons and grouping them on my home screen. Also having dockable apps is useful in some respects, like Google Chrome in Windows 8 mode. If I'm wanting to use it and keep it on top and without it being too much of an eye-sore, I can. An example of one use I have for it is below.
Why's this better than the alternative? Everything I'm doing in the right pane will not affect the left pane, so I don't have to keep bringing up my video player when moving through my workflow (nothing will overlap it). Having 2 normal windows side-by-side (like in Windows 7) will work, but say, I've not only go Visual Web Developer open, but SQL Management Studio or another browser for debugging? This actually makes it more convenient to use. And with 8.1, I can adjust it fairly easily to suit my workflow.
Of course, not necessarily just for tutorial videos, but also I could have a reference up there (like a reference book bought via the Google Play store or Kindle, I have one such reference book I use). Or maybe I'm using an online reference like MSDN. This is quite useful considering I'm not using a dual-monitor set up.
Though, I don't deny some of their choices in design have been poor, but they've shown in the past they can learn from poor design choices and improve on them for later releases, I suspect this is what Windows 9 will be. Despite it's flaws, I wouldn't say Windows 8 is a bad OS, because I would say each has its flaws, it's just a question whether you find it usable. I find it an improvement in many places on my user experience with Windows 7, but also some areas that I felt Win 7 did better.
