Pretty sure this isn't possible now, but it's something we'd love to see: the ability to prompt for input when you run a deploy task. This input would be stored in a variable (or variables). Use case:
We have a PDQ Deploy task that runs the User State Migration tool to capture the user profiles on a computer. The output of this is a directory with the same name as the computer. We then run a second task to restore the state to a new computer. This requires us to edit the task every time to specify the name of the source directory (i.e., the original computer name). If we were able to prompt for input, we wouldn't have to edit the task each time.