Tie the percentage complete on tasks to the time logged on the task. For example, if the planned hours on a task is 5 hours, and the assignee logs 2.5 hours of time, the percentage complete should automatically adjust to 50% complete rather than the person having to manually adjust it. If there are 2 people on a task and one person marks their task as "Done with my part" and the other person hasn't logged any time, the task should automatically adjust to 50% since on of the two people have completed the task. This should at least be an option on the Setup page where you can turn this functionality on or off. It seems to already be in place for the project percent complete but it would be nice to have this functionality for the task level as well.