I have checked the rules and confirmed that moderators are allowed to rant....

After an unhealthy amount of distro-hopping, I have just settled in with Mepis 8 / KDE 3.5.10. The reasons are many, including simplicity, solid performance, and the lack of any re-branding or "no-root-user" silliness. One major issue was easy and reliable GUI user switching.

Here's the rant:
What is so difficult about making a user-friendly and foolproof user-switching setup as part of the login manager? I've only seen 3 viable choices:
KDE with KDM
Gnome with GDM
XFCE or other "lite" distro + GDM

KDE / KDM is the hands-down winner. GDM usually works reliably (but not always), but is slower and clumsier. And it is not well integrated with the screen-locking. And---KDM has been superior for a very long time.

Why would GDM not be brought up to the KDM standard?

Why would not the XFCE community come up with a login manager which matches the otherwise excellent functionality and simplicity.

As good as KDE is, it would benefit from some improvements---eg: In a locked screen, display the user options directly (without requiring a click on "switch user") Also directly display the VT#, so one can just use ctrl-alt-F# to switch.
And--display this info in the corner of an active session....

What is so hard about writing a login manager?