Currently the only differences between the different sizes for any given missile launcher have been range and damage. However, the other two weapon types typically are more tailored for their preferred foes, i.e., Small versus Corvettes, Medium versus Destroyers, and Large versus Cruisers and Battleships. Usually, as it increases in size, the weapon has less Tracking (as their targets have less Evasion), it has slightly lower Accuracy, and it has higher penetration or bonus damage versus its preferred defense. This is not universal in all areas, e.g., Disruptor-type weapons keep the same +200% Shield Damage across all three sizes, but they still drop in Tracking and Accuracy.
Should missiles have a similar size differentiation? I could get behind at least the Tracking fall-off, although I would look at keeping the higher ceiling for Tracking (70% / 40% / 15%). One of the big complaints, with regard to point defense, has been that larger missiles are no harder for a point defense weapon to kill than the smallest. I would recommend multiplying the Hit Points for Medium weapons by 2 and Large by 4. I would also advocate having flight speeds having some +/- differences as well: if speeds are still in the ~5 range, I would want Small to be +1 to that and Large to be -1. My preference would be increasing speed by 100%, so a base 10 speed would have Small at +2 and Large at -2. (I’ve seen calls for 200% increase instead from the current 5 base (to 15), which would have Small and Large at +3/-3, and I would also like to see speed increase along with tech level (1-3 per).)
Depending on whether you feel that the above increases in missile hit points are actually a correction for a lack in survivability instead of just a new differentiation, missiles probably still could use some additional work in this area. Basic missiles could take their cues from Autocannons, starting with no versus-bonus for Small launchers, but then modest bonuses for Medium and Large (again, probably versus Armor). I'm interested in other takes on what might be done to differentiate between sizes of missiles.
Slightly off topic, but if they can’t get Swarmer/Whirlwind Missiles to draw PD fire with their 200% Evasion (i.e., tank PD), I would recommend changing them to either fire a burst of 5 or so lower power missiles that combine to a touch more damage than the current setup’s single shot (e.g., 5x 2-3 vs. 8-12 for Swarmer), or to shoot individual lower power missiles at a high rate of fire (0.40-0.50 days cooldown vs. 2.10). That would probably provide the tanking effect, and any lost damage potential from actually getting hit by PD is minimal (could move damage per or number of missiles/rate of fire up to balance further).
Should missiles have a similar size differentiation? I could get behind at least the Tracking fall-off, although I would look at keeping the higher ceiling for Tracking (70% / 40% / 15%). One of the big complaints, with regard to point defense, has been that larger missiles are no harder for a point defense weapon to kill than the smallest. I would recommend multiplying the Hit Points for Medium weapons by 2 and Large by 4. I would also advocate having flight speeds having some +/- differences as well: if speeds are still in the ~5 range, I would want Small to be +1 to that and Large to be -1. My preference would be increasing speed by 100%, so a base 10 speed would have Small at +2 and Large at -2. (I’ve seen calls for 200% increase instead from the current 5 base (to 15), which would have Small and Large at +3/-3, and I would also like to see speed increase along with tech level (1-3 per).)
Depending on whether you feel that the above increases in missile hit points are actually a correction for a lack in survivability instead of just a new differentiation, missiles probably still could use some additional work in this area. Basic missiles could take their cues from Autocannons, starting with no versus-bonus for Small launchers, but then modest bonuses for Medium and Large (again, probably versus Armor). I'm interested in other takes on what might be done to differentiate between sizes of missiles.
Slightly off topic, but if they can’t get Swarmer/Whirlwind Missiles to draw PD fire with their 200% Evasion (i.e., tank PD), I would recommend changing them to either fire a burst of 5 or so lower power missiles that combine to a touch more damage than the current setup’s single shot (e.g., 5x 2-3 vs. 8-12 for Swarmer), or to shoot individual lower power missiles at a high rate of fire (0.40-0.50 days cooldown vs. 2.10). That would probably provide the tanking effect, and any lost damage potential from actually getting hit by PD is minimal (could move damage per or number of missiles/rate of fire up to balance further).