Great job, use it, abuse it, and see what breaks. If you want to give the programming team a challenge, add a gyro and have them test field-oriented driving.
Don't be so down on mecanums, especially for learning. Using that robot as a test bed, you can easily swap the four wheels and experiment with traction wheels, omni wheels, mix of the two, etc.
Mecanums are also a good choice for a demonstration robot for fundraisers and sponsor presentations. Easy on the carpeting, and maneuverable in small spaces.
The more teams experiment with mecanums, the more you will see ingenious solutions for pushing.
