True, but you can boost up your firepower without using the systems slot. Proton Rockets are, admittedly, one-use, but are scary as hell coming out of an advanced's racks, pumping it to 5 dice + focus token.

This has two effects - firstly it gives you a punch at range 1. Secondly, it means your opponent really, really wants to shoot you down before letting you into range 1 - which draws fire onto a focused, sensor jammer-equipped TIE advanced; probably the ideal fighter to have your opponent shooting at...