Rather than push too much complexity onto the package itself I have taken the approach of creating a companion application, but it does require programming skills.
The first step is to log into mongo and convert the activities collection to a "capped" collection. This allows you to write a simple client to monitor that collection with a loop. Every time a new activity document is added your client sees it immediately. Then you have the fun of making any changes you want to any other data in mongo. In a prototype I had a checklist on a card and if all the items were not checked when a user moved it to the next column I put it back. If all checklist items were complete I removed the checklist and added a new one that related to the list it was moved to. In my dev world it takes about a minute to resolve. As my tasks run over days that is responsive enough.
My real goal is to hook this into a broader workflow. When a card hits a list I can run background processes to prepare the job for the next process step. Still playing with it, but I think it will have legs.