The next update to Windows 8 which was codenamed 'Threshold' is looking like it will be a brand new iteration of Windows.
There will still be a free update for Windows 8.1 at some point this year, and according to ZDNet there are indications that they are looking for ways to make it easier to use on keyboard and mouse.
The update is also said to include Metro 2.0 / Modern UI 2.0, which will all Windows 8 apps to run on the desktop if needed.
There were a lot of users turned off by Metro, so 9 needs to make some big changes if they expect people to pay for a brand new operating system just a few years later. All I really want to see is the option to just not have metro get in the way at all, that'd be good.