The problem with the PG hardline is it forces ships into specific roles. For example, the only times you'd use the widowmaker is on a vulture with a storm extender, or if you wanted to fly a Superlight.

A different approach would be to add an additional meter, like energy. We could call it 'heat'. This secondary requirement would have many uses in limiting a ship's potential, so that more can be added without it becoming overpowered.

If all modules produced heat to some degree, then it would limit how much firepower a ship could spew out at once. Unlike the current powergrid system however, you could equip your ship with lots of different powerful weapons, for a variety of single strategies to choose from in flight, or you could equip a balanced set of weapons for stronger, if less flexible, simultaneous fire.

Additionally, if heat was used for turboing, a power cell could be introduced that provided more energy to the ships that need it (Ragnarok) without providing infini-boost for every ship. This would give low-heat intensive, supplementary weaponry a special use, because they could be used while chasing an enemy where other weapons would quickly overheat your ship. This would be especially true if the weaker weapons were more energy efficient, which currently they should be anyways. (Flechette, Ion and Phase blasters, Plasma Cannon)