There a few points in there that I agree wit.
On Vista the sidebar holds the widgets and takes up screen space. On a Windows Mobile the screen estate available is limited, but if the sidebar was hidden by default and called on demand by either an onscreen button or a hardware button, then the widgets could be usable.
A widget can used to efficiently display valuable information updated by the web. Used in the right way, they can negate the need to load your browser and search the web for the information manually. Bookmarks and RSS feeds may be an existing alternative, but they take time to search and load.
On the HTC devices there is the Cube from TouchFlo (not TouchFlo3D). If a similar portal could be opened with a gesture input whih then had th information that you are interested in displayed in fullscreen glory and dismissable with another gesture, would this be faster than scrolling through externally updated rss feeds or using bookmarks to load a web browser and trawl through information on the off chance that it has been updated.
Handango, FreewarePPC.com and the Apple App Store all show that people are willing to download 3rd party apps to personalise their access and information. The fact that SmartPhones are built on this premiss shows that the market is out there.