I would suggest there be a mechanism to resolve dependencies when the system
is upgraded.
If what Update Manager does is simple apt-get dist-upgrade, chances are that
the system will accumulate with unresolved dependencies over the course of
time. It would be safe to build a dependency tree, similar to what debian
does, before packages are updated so that unresolved dependencies can be
removed in the first place.
Maintaining orphanaged packages as pointed out by jxself can be beneficial in
one way, but for a stable OS distro like Trisquel, it is always advised to
have resolve all dependencies so that the system remains robust.
