"It will be prettier and have cool multi-touch functionality, but that's not a reason to upgrade from Windows 7," says Kay. "There was pent-up demand for Windows 7 after Vista, and Windows 7 delivered what people needed. Windows 8 doesn't have that pent-up demand."
Microsoft has been good with providing backward compatibility, but if a business needs to develop new apps for Windows 8, if there's incompatibility between Windows 8 PCs and tablets, or if they need to add more IT support, there isn't a big upside to upgrading, says Kay.
Microsoft can afford to have Windows 8 struggle on PCs, he adds, but tablet success is essential because tablets are a factor in the high stakes mobility game that Microsoft is losing to Apple iOS and Android.
"Microsoft is in trouble in mobile and that won't change in 2012," says Kay. "The highest risk is Windows Phone. If Microsoft doesn't break through there it will be out of the smartphone game. With Windows 8 the risk is more moderate because it will run on more form factors."
But Windows 8 tablets may ultimately pay a price for trailing behind Apple and Google in the tablet race.
"Microsoft better hope that there will even be room for a number 3 when Windows 8 launches," says Kay.
Sign up for Computerworld eNewsletters.