The tiles do not make sense on a desktop at all — there should be a mechanism for starting software without taking over the entire screen real estate. It’s fine on a 8″ screen, not OK on a 24″ monitor at all. Fortunately, 3rd party start menu replacements exist.
Also, the lack of ability to run Modern/Metro apps in windows is horrible. You’re stuck with a Procrustean system where you can’t really choose app size. You should be able to run them in windows and mix them with desktop apps. Again, provided by 3rd party software like ModernMix, but should work out of the box.
What Windows 8 should have had is a touch mode AND a desktop mode, as well as the ability to limit the tiling to a portion of the screen. Actually, a fixed tile/sidebar area on a 24″ screen would have been AWESOME. Neither would have been difficult to implement — it’s a sign of MS’s ineptitude that 3rd party developers have to develop basic functionality.
Yeah, yeah, yeah. I’ve heard the shrinkobabble. People can’t really multitask, blah blah blah. All I know is that I often have a code editor, terminal window, photo editor, email client, documents, and web browser open all at once, and that they’re very easy to manage on a desktop where I can just click on a bottom bar for focus and resize however I want.