Or maybe a middle ground? For instance, consider Blackrock, who have the Dart; a fragmentation version of the swarmer that reloads. It comes in two types, Light and normal, with differences in total ammo count, how quickly it reloads, how many missiles it chucks out at a time, and the OP cost (4 for light, 8 for standard). The thing is, both are small missiles. So maybe an 'improved' version of the swamer that has a bigger ammo count, and a bigger burst with increased OP cost could be a useful alternative.
However I think the main issue is the swarmer does HE damage, which means it can, when massed, completely ruin non-fighter ships. So if you made it better, you'd get essentially a burst fire homing annihilator pod. Trying to balance that would be incredibly difficult, and enabling reloading (in both small and improved versions) would in turn make it a bit too powerful. Meso's suggestion for a reloading MIRV like from S&WP would be pretty useful; the nature of the missile means larger ships can clear the main missile before it hits, while smaller craft get minced by the mini-munitions.