The desktop can also be snapped into a sidebar with Metro apps. (Click for larger version.)
Snapping apps isn't a cure-all for the one-app-at-a-time restriction. For one, snapping only works if your display resolution is higher than 1,366 by 768; it simply doesn't work with anything smaller. Also, not all apps run properly when snapped into a narrow amount of screen space. For instance, when snapped, the Metro app store only shows the store icon against a green background, not the store itself.
Not all apps show up properly when snapped. The Windows 8 Store, for example, doesn't display anything when snapped. (Click for larger version.)
What the new-look Aero gives back
Much has been made about how the visual effects of Aero have been scaled way back in Windows 8, both for the sake of aesthetics and power consumption on portable devices. The Aero subsystem, which was introduced with Windows Vista, hasn't been completely removed; the underlying window-compositing functionality remains. But some of the fancier effects, like the rounded corners of windows and the blurred glass effects, are dialed down or absent completely. The Release Preview of Windows 8 offered an Enable Transparency option in the Personalization control panel's Window Color and Appearance pane, but it appears to have been removed in the final RTM code.
Removing the Aero Glass effects from Windows 8 saves energy and rendering power. The Enable Transparency option, which appeared in test builds of Windows 8 and allowed these effects to be restored, has since been removed.
Turning off transparency confers a few advantages. One, it consumes that much less battery power, which will be important to the tablet-and-notebook crowd that make up the majority of Windows 8's target user base. Two, it offers that much more visual consistency between the classic desktop and the Metro environment. Three, it means fewer UI elements to keep track of and render properly. To that end, if you're big on power consumption and overall responsiveness, turning off those effects makes for a net gain.
It's not inconceivable that a third-party company could add back in the missing style effects, via an app like WindowBlinds, but the dialed-down look and feel might work more in your favor than you think.