Tanks! AI Challenge - Game design improvements?

Hi Game Designers, I have tweaked the Tanks! tutorial game for use as a simple AI/programming challenge, but it is still based on the simple Tanks game:

Two tanks at pre-set entry points, enter the arena and can move and fire shells at each other.

What game design improvements could make this a much more fun challenge?



link to Tanks AI Challenge thread where you can download the project or you can use the Tutorial project in the learn section.