I think you should backup your database before making major changes. If there is an error, go to the backup.
I already do. But that doesn't fix all the problems.
Fix or find someone to fix the error in the install of the new package, then try again.
What's in the database is already broken so that wouldn't help.
I think magically doing something unexpected is a bad idea in this case and will lead to strange unexplained errors instead of a straightforward error on install.
There's nothing magical in an update.
What are those unexplained errors? (Could you give some example?)
