s4: Should we still support the "domain mixed mode"?

[Matthias Dieter Wallnöfer]

abartlet and others,
 
since I do some rewrite of the SAMLDB module of s4 at the moment (since I discovered that our actual not fits for future enhancements - discovered with tests and the WSPP documentation) I wanted to ask if we still should support the domain mixed mode.
This as you may know would require some extra case distinguishing regarding the group handling (mainly the "member" attribute handling).
If we aren't supporting it anymore we could save us some work.
 
Matthias