Limiting what weapons might be installed is good idea, because currently its no-brainer to go from avalanche x2, to Lasers x2, to Plasma x2. I suggest either:
a) not allowed to use two same weapons in one craft
or
b) different weapon slots: odd slots would be for "cannons" (cannon, laser, beam), even would be for "missiles" (stingray, avalanche, fusion ball)
There could be option called "craft armament rules", with a choice between those two above and "no restrictions"