I've been doing office jobs for about six years now and personally think that Win8 would be well suited for most office jobs.
Essentially in my time doing desk work, be it application processing, payments, call centres and helpdesk I've rarely needed more than two applications on the screen at the same time. My current role requires me to have an email client, a web based booking system, our database and access to another organisations database (read-only). Of course I also need general internet access and Office.
The full screen, snap to fit and drag to drop multitasking is surprisingly easier than the minimise, maximise, resize, reposition, etc routine that you have to do with desktop programs. I only need about five program shortcuts so the desktop and start menu shortcuts are pretty much wasted in my day to day duties and having to minimise every program just to get at a desktop shortcut is a huge pain compared to just clicking on the "Start Button" and going back to the Start Screen.
Of course there are flaws that need fixing and refinements that need to be made.
1) Microsoft have to make the start screen look professional and allow skins or colour uniformity for live tiles. My WP8 handset looks more professional with its blue livetiles on a black background than Windows8 current Fisher Price colour splash.
2) Microsoft has to allow files and folders to be pinned to the Start Screen.
3) Microsoft needs to help companies get their programs as Win8 apps.
Think of it from a tech support aspect, the more options for untrained staff is harder to support. The Win8 Start Screen is quite locked down, its got huge icons and fewer commands so while it takes longer to get used to its a hell of a lot easier to talk someone through it remotely. Power users are still better off with the Desktop but in your average large firm how many users are power users?