It seems like you may be referring to the workflow for Adobe's legacy tag Manager product, although you tagged DTM on your post as well so I'm not sure. In any case, DTM is focused around scenario-driven activation. What this means is that we recommend that you define the scenario ("Conditions") und...

This was a bug but it was fixed last year so I'm marking this as done.

Adobe Tag Manager is being discontinued at the end of 2014, but our Dynamic Tag Management platform (which replaces ATM) does have versioning and comparison for all changes.

This is being actively developed right now (along with many other improvements to our Analytics integration) and we're hoping to have it released by the end of February.

We are working to get this implemented ASAP. Thanks for the suggestion.

It looks like this is potentially a bug. Can you please report it with our ClientCare group by sending an e-mail to clientcare@adobe.com? Thanks! Shawn Reed Product Manager, DTM

We are definitely aware that this particular variable is missing from the UI. The reason why is because typically the products variable gets programmatically set using dynamic values rather than static values that might get set in a rule, so it's a bit tricky to build a UI for it. That said, we're s...

Thanks for the suggestion. There are already a couple of products/tools we are hard at work on which will address the exact scenarios you've described here. We don't have an exact timeline for them yet, but stay tuned.