Most of those aren't rewrites. A lot are completely separate products which were BUNDLED with Vista. Those can't count. IE7, for instance, has only minor improvements,
??? IE7 is a huge change (whether or not it's an improvement is debateable). IE 5.5 to IE 6 or 6.5 was minor. The move to IE7 was a bigger jump than any Safari, Firefox, or Opera release (since version 4). The Interface is completely changed, searching, tabs, Quicktabs, RSS, completely new rendering engine (doesn't even work with much of the old IE6 stuff), XPS built in, security, etc.
.NET 3.0 is also a bundled feature (though it is integrated somewhat into Vista.)
.Net 3.0 is to Win32 what Cocoa is to Carbon. It's a completely new (well at least the WPF, WWF, and WCF part) way to build Windows apps.
There was a 64-bit version of XP, so that is not a new feature.
True enough.
DX10 is simply another update to DirectX.
No, it's a
total rewrite of D3D.
XP -> Vista is perhaps like Panther -> Tiger (though the end result is still less than Tiger).
LOL. Panther to Tiger was a very very small update. Spotlight, Dashboard, Automator, CoreImage/Video... that's pretty much it.
Again, adding .NET 3.0 to the system was like adding Cocoa to the Mac OS. Then you got Microsoft's equivalent to Quartz/Quartz Extreme/Quartz2D (DWM), DisplayPDF (XPS), ColorSync, CoreAudio, FrontRow, Time Machine (Previous Docs), X11/terminal (Services For Unix/PowerShell), Exposé and CMD-TAB(Flip and Flip3D), Spotlight, Dashboard (Sidebar), new networking, Bonjour/Rendevous (People Near Me), Inkwell (Tablet), Voice Over, Speech Recognition, QT7 (WMP11), FileVault (EFS), AdressBook, New Finder, iCal (WinCal), iDVD (Win DVD Maker), iPhoto (Win Photo Gallery), IIS7 (Apache), OpenGL 2.0 (DX10), Unix permissions (UAC)...
Apple never added that much new stuff to any 10.x release and especially not from Panther to Tiger. 10.3 to 10.4 was more like Windows 2000 to Windows XP. XP to Vista is like 10.1 to 10.5. It only stops short of OS 9 to OS X because they didn't change kernels (although they did add one with 64-bit).
Vista was SUPPOSED to be somewhere between that and OS9->OSX. But they had to cancel that. Now it is supposedly Vienna which will do that.
Vienna is a minor release. Essientially Windows Vista R2 (Release 2) just like Windows Server 2003 has an R2 version. There's no reason for MS to ditch all the new underpinnings they just switched to. Hell, they only switched to the NT kernel (for consumers) 5 years ago. From what I've been told (from different sources than Thurrott), "Vienna" will be mostly the stuff they cut from Longhorn (WinFS etc.) and the interface stuff they didn't get around to building because WPF wasn't finished.
From Winsupersite:
Q: So is Vienna going to be a major Windows version?
A: No. Windows Vista was a major release, and Vienna will be a relatively minor, or interim, update. Microsoft is currently on a development path where every other Windows version is a major release.
Q: When will Vienna ship?
A: Microsoft currently plans to ship Vienna in 2009, about two to two and a half years after Vista. The next major release of Windows is expected two years after Vienna, in 2011. (Windows Server updates are on a similar cycle.)
Q: What features will be included in Windows Vienna?
A: Microsoft hasn't publicly committed to any features for Vienna and the company is currently still deciding what this next Windows release will look like. We do know a few things about Vienna, however: It will include a new version of Windows Explorer that is being built by the same team that designed the Ribbon user interface in Office 2007. It will likely include some form of the "Hypervisor" (Windows Virtualization) technologies that will ship shortly after Windows Server "Longhorn". It will also likely include the WinFS (Windows Future Storage) technologies, though they won't be packaged or branded as WinFS.