a power-user has little choice unless he/she wants to go to the trouble of installing an alternate shell
If "apt-get install [alternate desktop of choice]" is too hard for you, you are not a power user.
Seriously, kids these days. Back in my day*, linux was about having multiple choices for everything - not just the power users, but the regular users would all customise their desktops in whatever way suited them, and we liked it. (Well, most of us did. Those who came from the windows or mac worlds curled up into a ball and cried when presented with multiple valid options to choose from, and insisted that somebody else choose "the best" to be preinstalled for them. And thus, Ubuntu was born to give them what they asked for)
* I'm barely out of my teens, but I'm old enough to remember when "power user" meant "someone who'd customise their desktop by hacking the C code"; Then it got degraded into "someone who could compile from source without modification"; then "someone who'd install packages from outside the distro's repository"; then "someone who'd install packages from the repository to replace the defaults"... and now apparently "power user" means "someone who can install ubuntu and doesn't change the default settings". This makes me sad :-(