Missile interceptors do not need more then 4 slots, plus the shorter the missile the better it turns. I do not know much about the thrusters but the variable thrusters main benefit is fuel efficiency which allows the turning thrusters to be used longer. The short range is used for greater speed and acceleration which I think is not necessary plus I am going to make a type 2 variant with 2 lasers mainly for missile interception due to the low dmg output, that also means that I will replace the laser on the type 1 with a standard gun.