I've been using the Windows 8 developer preview now for long enough to come across a number of design flaws that MUST be addressed for the OS to be usable on desktops, notebooks and tablets.
Note: I know that this is a developer preview, and not a beta or release candidate, and that nothing is fixed in stone, but if we don't make a noise now, it might be too late by the time we get to the beta stage.
#1 - Metro multitasking = two apps
Right now, I'm working with six different applications. When it comes to Metro apps on Windows 8, multitasking means having two apps on the screen side-by-side. That's it. For the causal user, that might be fine, but for power users, Metro offers little more than a LeapFrog 'My First Computer' experience.
The limit of having two app on screen at any one time is crazy and needs a total rethink.
#2 - Mishmash of Metro UI and Aero UI
I find the fact that I'm continually switching between the tile-based Metro UI and the glassy Aero UI at best jarring, and at worse illogical and confusing. Switching between Metro apps and traditional applications is particularly painful, and the idea of trying to do any real work that way doesn't fill me with joy.
At present, the Metro UI is thin veneer over the classic UI. A good example is Control Panel. One minute you're seeing a Metro UI, but a single click is all it takes to kick you into the classic UI. Metro UI is a veneer that doesn't work for either desktop or tablet users.
There needs to be a total reworking of Windows to allow two separate UIs, because this current situation is laughable.
#3 - Metro is nothing more than a gimmick on the desktop and needs a kill switch
While Metro makes some sense on tablets (it makes sense if you're not in the market for a Windows tablet to get legacy support and a familiar environment), I can't come up with a single good reason for this UI to be on desktops, and it's hard to make a case for it on notebooks. I don't see touch-based computing becoming mainstream on the desktop, and I don't see Microsoft shoving the Metro UI down people's throats changing this.
With this in mind, it makes no sense - none at all - for Windows 8 to boot into the Metro UI by default. I've gone to the point where I just see it as a secondary log-on screen that I have to get out of the way if I'm to get any real work done.
In other words - Metro UI needs an official kill switch.
Note: Check out my ZDNet blogging buddy James Kendrick's thoughts on Windows 8 on a tablet.