Managing them is usually not that hard, because vast majority of them are just duplicates of same issue. Basically all problems come with the fact that dbconfig-common really does not behave nicely when database server is not configured and user tries to configure it. I know people should just answer no to first question, whether to use dbconfig-common, but they don't and it then horribly fails.
Today I finally decided to ignore all errors from dbconfig-common in our packaging scripts, so you will get an error, but the package will be installed. As it seems that this is what most Ubuntu users expect after all.
This also shows huge difference between Debian and Ubuntu users - such bug has never appeared in Debian bug tracker, but has zillions of duplicates in Launchpad in various incarnations (LP#618852, LP#621569 and the most favorite LP#456674).