(1/7) Limit economy to 5x # of planets (or 5 if no planets)
7/11 Another crazy thought (maybe to be implemented later): Base-4 (instead of Base-5) Economy. Currently, your credit cap is based on the number of planets multiplied by 5. What if it was multiplied by 4 instead? All the costs in the game (and starting money) would need to be adjusted, obviously, and then cost 4 (instead of 5) would be the cost to avoid.
Advantages: fewer coins required per player (20 instead of 25). Military becomes more relatively more important during attacking (with or without moving military values higher)
Disadvantages: less space to play around with the costs of things. Starting planets would all have to cost 0, 1, 2, or 3 (instead 0-4 as today).