[thefro526]

It seems that the rules allow for a theoretically unlimited amount of Air Tanks as long as they do not violate any other rules.

If you're truly afraid that this may change, then let me propose this solution:

Design your robot to work with 4 Air Tanks and a compressor as allowed in previous years, then add as many air tanks above the 4 as you want to allow for a greater amount of stored air. If the GDC comes out later on during build or competition season and reduces the amount of air tanks allowed on the robot then you'll be able to run with the new limit (assuming the GDC would go down to 4 tanks sized like previous year's tanks) because you designed to work with that minimum.