That would depend entirely on the range of this weapon. Not having to stay in range of the other's death cannons is much preferred for smaller ships. You seem to be limiting their mobility, not increasing it.
As I understand it, ship combat speed and maneuverability is determined by the hull itself and OP modifications whereas lateral traverse speed is determined exclusively by ship class.
If this is true, small, fast ships with primarily forward weapons are at a disadvantage when strafing their targets. Essentially they must sacrifice speed to stay on target. The idea I was working towards is a weapon that allows these ships to fully utilize their speed while still keeping effective levels of firepower on target.
The other factor is that small ships usually have very limited shield coverage and often have to contend with incoming fire from multiple vectors. This weapon would potentially allow a player to maximize their shield effectiveness without sacrificing as much shooting time. (Granted, this would be much more advantageous for hardpoint heavy ships than for ships with good turret coverage)
Of course, both the previous disadvantages exist for the sake of ship balance, so it is possible that this would be rather overpowered unless carefully tuned. As you mentioned, range would be the major factor in deciding how effective this weapon would be at its intended role.