Huh? You don't need the terminal. You can chose the environment in the login screen, there's a drop down menu besides your name. Not exactly intuitive, but very easy to find out using Google or a forum. If you want Gnome 3, you can install it from the repositories (again, no terminal required, at least not in 11.10), and it'll be there in the drop down menu.
Yes I was speaking of Gnome3. And No. It's not only "Install it from the repositories". Maybe it worked easily for you.. but for me t'was horrible. And yeah, I ended up having to mess around in the terminal and lynx to solve the problem (I had no other computer and was not going to always reboot to windows to Google something while tidying everything up). But yeah you can always say that's because I'm a noob, and was unable to do it right... but that's exactly the problem. A "newbie" should not have that kind of problem.
Sorry then. I guess it's only foolproof when it actually works#. My own upgrade experience wasn't for the faint of heart. I hope it was a learning experience, at least; it usually is for me. ;)
Beginners shouldn't have this kind of problem; but put another way, beginners shouldn't mess with this stuff unless they're willing to have this kind of problem (I'm sure most of us have been there, willingly).
# I'm not sure Ubuntu is particularly bad in this regard. It seems to be universal among all the operating systems (and everything else, for that matter). But I guess Linux is more likely to drop you to a shell, which might be scary for beginners.
Zero understanding of *nix required here.