I have always found Ubuntu's stock-desktop rather lacking. God forbid you should want to change the default look of the installation, you're required to install a ton of additional bits and use gnome-color-chooser. My thoughts on the announcement:
1: Dropping gnome shell - Probably good, as Ubuntu's current implementation of the gnome shell is horrible. I'd prefer that they fix their implementation though.
2: Adding compiz by default - This is good, as many of us do this anyway.
3: Unity (based desktop experience) - While I want to see what they have to offer prior to passing judgment, unity (in its current form) is not something that I would choose to put on my PC.
4: Required 3D acceleration - The technical term that comes to mind is "retarded". Even those of us with 3d accelerated hardware are periodically without acceleration.
I'll probably take a peek at their plans this weekend, so that I have more information than what is provided by the "news-entertainment" websites.