It would be usefull to postpone the uninstall of shared libraries or atleast their .so files would be postponed until revdep-rebuild is done and the old versions are no longer needet. This would avoid breaking half of the installed packages when widely used libraries like libjpeg, libogg oder libpng are updated.
Steps to Reproduce:
emerge -vuD @world #when libjpeg has an update
half the system is in an anusable state since the old libjpeg.so.XY is no longer pressend
remove old versions of .so files as a final step in revdep-rebuild
a list of .so files that are obsolet could be maintained. revdep-rebuild could check this to see if anything still depends on then and remove them if this is not the case.
This sounds a lot like FEATURES=preserve-libs and @preserved-rebuild in portage-2.2_rc* (see bug #240323).
if it is comming anyway, i can close this as invalid