I'm kind of agreeing with you there. I'm sure the changes to Aero will receive many more tweaks before release (look at what other Windows versions looked like in the first pre-release), so I'm not too worried about that.
But I hate the start screen. It's nice as an option, but like I said in the other thread, there has to be a way to open an app or do a search that doesn't take over the entire screen. It's ridiculous. This UI is completely unsuited for a desktop.
Over the years, as the UI changed in new versions of Windows, I've always used the new stuff. I loved the start menu change in XP, with the frequent application list and system stuff on the right. I loved the addition of search in Vista even more. I loved taskbar grouping since it was introduced in XP. I love the Win7 taskbar.
This is the first time that there's been a change to such a core part of Windows where I really dislike it. There has to be an alternative to this start screen stuff by RTM, or for the first time ever I might have a solid reason not upgrade.
Who knows, maybe the start screen will grow on me (unlikely) or maybe they can mold it into something that's more suitable for the desktop and mouse usage, but it will require major changes.
It all looked so nice and reasonable in the keynote too, but when using it my reaction was just instantly negative, which has never happened to such a strong degree before with any UI change MS has made that I can recall.