(keeping in mind that releasing is not typically my problem, so I'm not an expert..) We do have that capability to some extent, but it's a hard problem, especially given that it then results in a large explosion in the number of combinations we have to test with the same rather small pool of resources: "is library at foo, or foo+2, or foo+3?"

So essentially, it all boils down to testing. If we manage to get the releases out reasonably quickly, it shouldn't matter all that much anyway.

Well, yes, but there's a line in the sand between acceptable, and unacceptable. You can't release until you cross that quality line unless you want a lot of very angry people.