Have you ever seen a Metro-styled business application? No? Have you even bothered to look at VS11 to see what kind of capabilities Metro-styled apps can have? No?
Then you have NO CLUE about whether or not Metro is "useless for productivity workers". Seriously, tone down the hyperbolic rhetoric.
AFAIK, "productivity workers" are used to applications that have textboxes, buttons, comboboxes, listviews, radiobuttons, checkboxes, grids, lists, richtextblocks, etc. Guess what. Metro-style apps can have all of those controls and more. The only difference is that application windows have no chrome.
I personally don't like full-screened applications. I don't even like the tabbed UI paradigm. However, that doesn't mean that most other people are like me.