What i personally expect from win 9:
1) NTFS with real sym and hardlinks, no registry crap.
2) Global menu bar option for applications insode panels ( main menubar inside panel)
3) a grey theme design with nice borders for buttons
4) a launcher/start dock with opened apps on the right or bottom side.
5) a desktop icon / fences like full screen start menu woth real icons
6) nicer and rounder min max close buttons.
7) wine integration into the system: https://www.winehq.org ( yes the windows emulator schould also be integrated to win7 with a patch ( really necessary) !!!)
8) the new metro ui apps windowed with menu and toolbar.
If microsoft implement these 8 points in their systems i would buy it. if not win 7 is enough for me.