Add a 'Dependency' Boolean property to the SMS_TaskSequence_* SMSProviderObjects that will settle whether or not any given step has resolved its content dependency. When you move Task Sequences between sites these dependencies aren't resolved and Task Sequence steps will reference content from your old site. This makes it hard to perform any kind of automated correction without writing very inefficient code.

It doesn't have to be named 'Dependency' but Task Sequence SMSProviderObject that can have content dependency should also be able to tell you whether or not it's successfully resolved (mapped is maybe a better word? I don't know) when you're enumerating Task Sequence steps with PoSh.