I hope it's the nadir. It can only go up from there.
In all seriousness, the more I think about it, I'm not so sure that business users, in general, wouldn't take to the Metro-style interface. As a developer, I would go insane without being able to tile or cascade multiple windows. I prefer working from a notebook, so I don't have multiple displays unless I go to my desktop. But for consumers and even business users, I regularly see them use applications full screen anyway. Of course, this is far more a drastic change than going from menus + toolbars to the ribbon. So we'll have to see.
But the cynical side of me isn't thinking that Microsoft is encouraging everybody to go all Metro because they think business users will ultimately like Metro and think it's best for them. I think Microsoft is doing so because they want to encourage third party developers to sell their products in the Windows Store. Microsoft can only get that 30% cut if it's a Metro app.