Some of these comments I have seen on FB and Twitter are just silly. For those that think "this is too much change"... did you even watch the key note?
1) The new Metro UI is an optimized experience for touch. You still have access to the traditional desktop experience. The user is in control of their experience. The developer is in control of optimizing the experience they want their customers to use
2) The new WindowsRT runtime live SxS with the traditional API stack. You don’t have to compromise either way. You can optimize for both.
3) You still have full keyboard and mouse access to Windows
4) A core fundamental is backwards compatibility. So whatever worked in Win7 will continue to work Win8
5) The experience changes in Windows do not boil down to a simple UI skin. There are fundamental changes made to the entire OS (Kernel up) to optimize for different form factors, hardware devices, battery life, peripherals, etc
6) did you see the HW lineup? Low-end to super high-end... same OS, same experience, optimized for the hardware available.
So either a) You did not watch the keynote (if that is the case then you should do so ASAP http://www.buildwindows.com/) or b) you simply hate Windows and don’t care for any of this (then just say it and stop pontificating how "This is too much of a change" and "it will be a long time for people to adopt") or c) you are paralyzed by change
For those in the b) bucket... did you have the same negative feedback for Apple when they introduced all their new constructs, dropped flash support, locked out all hardware vendors? If yes, then great... at least you are fair. If not, then you will soon be in the minority. Keep enjoying shelling out $500 - $1000 dollars every 9 months to get your iDevice fix.