Add a "Point System" to tasks
I have said before (in another post) that this is the BEST task management system that I have worked with in more than 30 years. I, and my boss, LOVE IT!
What if you add a "Point System" to each task? In other words, the "task-master" would assign 1 to 10 points for each task created. Now, once the task is completed, the person to whom the task was assigned receives those points, which will be stored in his/her vault. Once a certain number of points have been earned, this can translate to something tangible (ie - free movie tickets, dinner out, etc).
This added feature would certainly enhance the mobile version of this software if created similarly to a game. Work is all fun and games again! :)