Running Ubuntu 10.10 with a gnome-shell build from the git repository, and I have to say, I love the change. The minimize and maximize functions themselves are not gone; as the summary says, you can still double click the title bar to maximize. If you want to minimize, you can right-click the titlebar, then click minimize, or using ALT+F9.
I think this is a great design change. In Gnome 2.0 and less, like windows, you would minimize windows to make room/less clutter for windows you're actually using at that top. Now, instead of minimizing, a better method is to move it down a screen (right-click, move to workspace down), or zoom out to activity view, drag the screen from one screen to another. I find when I have a lot going on -- multiple browser windows, terminals, ftp client -- I use this a lot. It comes in handy being able to separate each website you're working on, each server, into it's own workspace, free from intrusions and other unrelated stuff.
Good job Gnome devs!