Just to make sure we're on the same page, how did you try launching it in Vista?
From a cmd.exe prompt.
It asked for elevated privileges nicely (via a UAC prompt), opened the Windows Features window, put "Please wait..." in the rectangular area below the descriptive bit of text at the top, and I did as it suggested.
I'm doing it now, in fact. Waiting, that is.
Ooh. I was too impatient this morning. It's populated the window with the stuff I'd expected to see.
You can also try launching it with the following command line:
Yes, that works too.
Okay, so for what it's worth, it works in Vista. The "it takes ages to populate the dialog" thing might just be because this machine's a few years old -- and, of course, it's running Vista