unfortunately there's not really a good way to do this other than by employing a very strong governance plan.
1) I run reports to regularly discover when new templates are created and I audit them at that point, if they were not created by another admin.
2) In general, because we have so many people in workfront now, our practice is to assign ROLES to the majority of template tasks. This makes it easy/easier to spot the people assignments and cross check them against the people section.
3) For the existing templates, we employed a cleanup effort involving the templates themselves. So we went through a set of reporting to discover which ones were not being used anymore, and deactivated these, so we would have fewer templates to audit. Then it's just a matter of looking at the template tasks, making a list of users assigned, and deleting anyone who isn't assigned to anything or has no other business being in the template. For some workflows they do have a few people who feel like they need to be in every project, but this is something we check in with the stakeholders about before we do all the deletions.
Thanks so much for taking the time to explain. I was thinking more about how you compare the People section to the created project's assignments, not so much the template - do you have a method for that specific cleanup process? Or maybe you're saying that since that's so hard to do, governance beforehand is way more important for you?
One of our pain points is when someone is accidentally assigned to a task, and nobody goes into the People tab to remove that user.