According to new Windows 9 leaks and rumors, it seems we could be in for some dramatic changes by the time the first public preview of Windows 9 rolls around (probably on September 30). The most recent leaked builds of Windows 9 (codename Threshold) indicate that Microsoft will finally fix the awful upgrade process that has plagued Windows for almost two decades, replacing it with a one-click upgrade system. Perhaps more excitingly, another source says that Windows 9 will formally split the Metro and Desktop interfaces: Tablets will be restricted to Metro, while laptops and desktops will be locked to the standard Desktop interface. No longer will tablet users be forced to fumble around the legacy Desktop — and no longer will mouse-and-keyboard users be thrust unwittingly into various Metrotastic applets.

First up, the improved upgrade process, as reported by Neowin. The most recent builds of Windows 9 (which are labeled “Technical Preview”) include a one-click upgrade process for moving from one build to the next. The update is performed in much the same way as current patches: You open up Windows Update and then click a single button to upgrade your build of Windows. This is obviously a huge improvement over previous and current incarnations of the Windows update process, which have invariably had shockingly high failure rates. Sadly, I think almost everyone reading this story will have, at some point in their lives, spent hours or days trying to upgrade Windows. Hopefully, with Windows 9, those days are behind us.

What isn’t clear, however, is whether this will affect the upgrade process from Windows 8 to Windows 9 — or whether this is purely for upgrades after Windows 9 (9.1, 9.2, 10, etc.) I have a nagging feeling that the upgrade process to Windows 9 will still be pretty horrible — but hopefully it’ll be relatively painless forever after. This new upgrade process is a sure sign that Microsoft is serious about its move to a rapid-release cycle (which in turn is vital if it wants to compete against the Apple and Google competition).

Next, we have WinBeta saying that Windows 9 will formally split the Desktop and Metro interfaces: Your Windows 9 device will have either the original Desktop or the newer Metro interface — not both. This is a big change for both tablet users and conventional mouse-and-keyboard users. As far as tablet users are concerned, all of the legacy ties to the Desktop will be gone: Metro will be front and center, and you won’t ever have to visit the Desktop interface to run Microsoft Office or view the Control Panel. For conventional PC users, you won’t ever see the Metro interface if you don’t want to — though apparently there will be an option to use the Metro Start Screen instead of the resurrected Start menu if you wish (presumably this is how touchscreen hybrids, like the Surface Pro, will operate). Mouse-and-keyboard users should still have access to Metro apps by running them in a window on the Desktop.

Rounding up other rumors and leaks, Windows 9 will probably also include smarter, more lively live tiles — and there could be a notification tray, too. The removal of the Metro interface for mouse-and-keyboard users links in nicely with the previous rumor that the Charms bar is also being removed. As far as we’re aware, virtual desktops are still coming, as is the Cortana digital assistant (though I have no idea if she’ll be in both versions of Windows 9, or just the tablet/Metro version).

So far, then, Windows 9 is shaping up to be very interesting indeed — though it’s hard to ignore the fact that this is essentially everything that Windows 7 and disgruntled Windows 8 mouse-and-keyboard users have been asking for all along. The mind still boggles at how Microsoft managed to get Windows 8 so wrong for conventional PC users — but hey, better late than never.

To be brutally honest, though, it’s not like Microsoft’s share of the PC market was ever at risk. It sounds like Windows 9 will fix a lot of what was wrong with Windows 8 for mouse-and-keyboard users, but an even more pertinent question still remains: How does Windows 9 help Microsoft get more than a few percentage points of the mobile market?