We discussed that #feature in the past and I agree with @giacomo here Cherry pick updates in Software Center :
To be able to cherry pick updates, you need a deep understanding of rpm packages interactions and system libraries.
That proposal was not able block dependencies, so I abandoned it because it solves the problem partially.
What changes with “software update policy” is the set of repositories enabled during updates.
I’d name it “expert” because it requires some expertise about what’s happening, as we learned during the past week, when some people just pressed “update” even if a “new distribution is available” warning was displayed. The “conservative” policy would make that kind of mistake impossible.
…but please suggest other names! I’m sure my proposal can be improved!
Both policies wouldn’t save us from a badlock-like regression coming from upstream. If that happens again in the future, the only thing that can help is a careful review (and backup) before updating.