I'm very happy that you can create templates and automatically add assignees/watchers, however one thing that doesn't happen is that when a template is loaded to a task, the people that are added automatically as assignees aren't notified that they've been assigned to a new task.
I have it set to notify me when any new tasks are created, however a colleague of mine doesn't like to see all of the new tasks coming in, so when a new task is created an a template is loaded, he gets no notifications about being assigned these new tasks (specifically the subtasks/checklists). This can create an issue if he is the first one needed on a specific tasks, then someone needs to tag him in a comment to make sure he sees the new tasks.