Show config differences during upgrade when reconfiguring services
When upgrading (in my case from 3.1.2 to 3.1.6), the admin can choose whether he wants to reconfigure all or any services. But there is no (clear?) indication as to what exactly will be changed and how manual config changes will be kept (hint: not at all, but comments will in some cases like Postfix, which is strange).
I suggest that the behaviour of the upgrade script is altered to display some kind of diff for each to-be-modified conffile and allow users to choose between the old version, the new version, editing the conffile or keeping both (X and X.new), something like Debian does for conffiles. This allows quick migration of manual changes and doesn't confuse users.