Ask and ye shall receive. Why you shouldn’t use BuddyPress is a lot harder to answer, since it’s actually really useful for a lot of weird things!
So you want to use the admin bar, but you need it to have different menus? That’s a little complicated but by no means impossible!
Do you have a plugin for use on WordPress that makes a menu? Is it BuddyPress or Network related? You need to read this right-freaking-now. Do not pass GO, do not collect $200. WordPress 3.1 will make your menus vanish!
Customizing your sidebar to have a cool and sexy profile accordion is actually pretty easy!