Sound settings could be changed at one place and not at four different ones to use the sound device/configuration he wants.
Gnome remembers the used mixer per sound card so there would be no need for change it after a PCMCIA or USB sound card is removed or added.

Other information:
To test this the System needs two recognized sound cards. I assume that in all options the external is the default one.
Under System - Preferences - Sound it is possible to choose a Device. I choose the internal one and mixer PCM (for keyboard volume change). A standard user would think that's it, now internal sound card is the default one but if I double click on the volume applet in systray my external is still the default one under Gnome Volume Control. So I change it under File - Change Device - to internal. Now it should be OK but if I want to change volume through left click on the systray volume applet symbol it is still the external mixer so I have to click on the volume applet symbol with the right mouse button and choose Preferences to set the sound card and mixer.
Now it should be Ok but if I play a sound file it is still routed through the external since all these changes has no influence to asoundconf so I have to run "asoundconf set-default-card Intel".
Now it is working after changing settings at four positions. And most of the settings have to be changed again after switching sound card.

Another point is that Gnome normally uses the first mixer of a sound card to change volume which works sometimes but not always. If I change this it remembers the configuration only for this configuration and sound card. If I remove sound card, restart and plug it in it uses the first mixer device again.
So saving of the mixer configuration per sound card would be great.