YES!!! What about deceased individuals? We are a hospice org. It is bad form for a widow to see we are sending emails to her deceased husband that we cared for and know for certain has passed away. There are so many reasons to remove someone from a workflow. I set up a workflow of steps to take in attempt to secure sponsorship. If I'm able to get a commitment early on in the process I want to stop the "ask" workflow and start the "fulfillment" workflow. Other examples; a constituent calls and requests no email sent unless it is specific one to one communication- but they are on a workflow with emails in it. You could have a workflow centered around inviting people to participate in an event- once they register they should stop getting "please register" emails.

I'm about to delete an entire workflow because I assumed that this was possible. It should definitely be possible to remove someone from a workflow.

There are a lot of reasons I could think of do need to manually remove someone from a workflow. This limitation has made me hesitant to start using workflows, because the risk is to big that someone might accidentally meet a condition and need to be removed, but putting them in the workflow could be really damaging to the relationship (e.g. welcome series for a duplicate record that is not truly new and does not need to be welcomed).