I few things to add as well. I certainly hope against hope that this kind of feedback isn't below the notice of Microsoft. I think some of these recommendations are well and good. Virtualization, great, Sync, great, the signed software thing is going to be controversial, and I would only support it if it could be disabled. But there are couple of larger concerns that IMHO should take precedence.
1 - Size/Bloat
First of all, size, efficiency, and scalability should be the utmost concern. For example, the entire reason Windows 7 was favored so much over Vista. Sometimes we don't want MORE features, we just want more, speed, stability, security and refinement. Stability and security go double for the enterprise market. Furthermore, more people out there are moving down to Atom processors and tablets then moving up to i7 Sandy Bridge monsters. I think there is a real opportunity with a next gen windows to scale it down. What I would like to see is a fully functional windows operating environment that can run ANY windows software lean enough to operate on a tablet. Having a pretty, zazzy, visually stunning interface with lots of complicated searching, indexing, pre-fetching and intra-OS chat would probably inhibit this. I would rather be able to run Excel, Photoshop CS5, and DirectX 11 on a tablet than have transparent window borders and animated transitions. Even the performance freaks would line up for the minimalist version if the spared resources gave them 2 more fps in Crysis.
2 - Inappropriate App interface
The article lauds the Windows Phone 7 Metro interface. While I agree its visually appealing and there are absolutely organizational lessons that could be learned relative to the start menu, I don't want an App/Widget interface to replace or complicate the freely customizable desktop or normal file navigation. First, it likely runs counter to point 1. It usually involves big slash screens and animations. Second, it creates these complicated closed systems. We already have "big friendly buttons", Icons, and I wouldn't want to push devs to complicate that any further. Apps are on a phone aren't better than applications, they are a compromise to cope with the limitations of a 4 inch screen. Sometimes I want to treat my pictures as files, and I don't want to have to contend with the constraints of a meddling Media Center type application to explore, organize and navigate. Knowing where things are is as important to me as convenient access. I'm not against separate 'slide show' or organizer applications, but that shouldn't be core OS functionality.
3 - Control
I'm fine with paternalistic and opaque defaults to prevent casual users from getting themselves in trouble. I totally understand the impulse, and its important for the bulk of casual users. But for devs, system admins and people trying to get those 2 more fps, really really granular control is very important. This is part of what drove me nuts about Vista, and a little bit about 7. Let me give you an example: when I went to take the Bar exam (you know, for lawyers), everyone with windows Vista had a critical update, causing a bit of scandal and delaying the exam. Furthermore, the secure exam software was incumbent on restarting into an alternate shell, and the update botched the key restart for a lot of people. Even a casual user should have to rubber stamp something like that. More to the point in the article - there should ALWAYS been an OPTION to (once / always / never) allow unsigned apps; there should always be options about why and how often the OS checks the internet for any reason. All of the neat features should allow opt-outs for the sake of performance or for any possible interference they would have with software, security, or a Sys admin's job. Furthermore, I think it would be better for everybody to consolidate more these settings in a grown-up master control panel, instead of bewildering the causal user with those side-pane options, or causing devs to hunt for settings and war with user-friendly over-simplicity.
4 - Legacy
One final note - legacy software, enterprise and otherwise, is the primary reason people may people and businesses have stuck with Windows - Microsoft should never forget that. XP mode/backwards compatibility (even across the 32bit-64bit divide) should be flawless, efficient and integrated.
Apple has done well with a very closed environment, and linux is a wide-open, un-standardized free-for-all. The beauty of Windows is supposed to be that its the easy-to-develop-for space in-between. Before I get flamed, let me just say this all my humble opinion. While I consider myself more than a causal user, I'm not a programmer, system admin or developer. I'm just a home user / gamer / enterprise user, and this my perception of people's sensitivities in an OS. They want compatibility with the software they need and they want it to run quick, stable and secure, period.