I would code some more options for the CM's of AvA and SEA. These would include ability to set different paramaters for winning the war, ability to choose which maps and in which order they would rotate, ability to hold arena settings through the resets.
I would also improve the AI capability to include ground vehicles and better robot pilots, and enable AI mission generator for said CM's.
I would implement a scaled down version of Combat Tour in the AvA arena using the volunteers to take up some of the workload.
I would continue to develop planes and vehicles that would be useful in historical set-ups regardless of their popularity in the LW arenas.
I would restrict the new H2H system in such a way that it doesn't destroy the arena system we have now.
I would then consider other things that weren't quite so self serving.
