I.e. a display like the current update suggestion message for Plone
itsself.

3rd Party Updates installed by buildout that need migrations should be
able to hold a "untouched" flag like the "safe download" database in
MacOSX until the necessary migrations are finished. The Quickinstaller
still provides this in a more general form, but there are some cases
where we need more info at the right place saving support time. Maybe
I am overseeing something that is already present.