I think that the MLRS is still a little too good, but it’s much more balanced now that you actually need to bring something along to take care of shields for the MLRS frigates. However, having a shield penetration of zero may have been a bit extreme, and deviates rather significantly from the ‘standard’ role of missiles in game - taking down shields.
It’s still a bit too accurate, so you might want to reduce tracking further - possibly consider going for really low values of tracking, like for example 0.6 (this is the tracking speed for Cruiser Plasma Launchers) or perhaps around 1.0 (which is about what the Parasite Plasma Slinger is, and that weapon is the one which I think is most similar to yours in the base game), and upping the damage of the missiles slightly - this weapon has more than enough fire volume to make up for inaccuracy in targeting. I don’t really think the alternative of further reducing the warhead damage is reasonable at present. I may be getting the wrong impression based off of the name, but I feel like this should be an inaccurate weapon that gains utility from the theory of ‘if we launch enough missiles at them we’ll hit the target eventually’.
All other missiles in the base game, aside from EMP, Antifighter, and Decoy Missiles, have enough shield penetration to go through the shields of any ship of at least their own weight class (frigate missiles will eventually bring down frigate shields, cruiser missiles will eventually bring down any cruiser shields) and several (fighter torpedoes, frigate torpedoes) have the ability to bring down the shields of things well above their weight class. By contrast, your missiles join the Frigate Antifighter Missile, Frigate Pulse Laser, and Decoy Missile Launcher as the only weapons in the base game which will never take down even the lightest of frigate shields. This is not a bad thing, it’s just a bit counter-intuitive since someone looking to arm their ships with weapons might go ‘Hey, a missile launcher! Great, now we’ll pick something to do damage to the target after the shields are down.’ if they don’t read the weapon statistics.
This, however, is entirely your choice - there is nothing in the game that says “All missile weapons must be at least as effective at penetrating shields as they are at penetrating armor, unless they are intended for use against fighters”, it’s just an implied feature of the game universe that missile warheads are more effective against shields than hulls. Nothing wrong with adding a weapon that doesn’t really fit the general trend (after all, the Swarm did it with a beam weapon better at breaking shields than armor). If you do decide to keep the MLRS as performing better against armor than shields, you may want to put some hint of that in the weapon description.
If you want to keep the weapon as a high accuracy, high rate of fire missile launcher, you might want to update the description - calling it ‘buckshot with missiles’ and naming the weapon a Multiple Launch Rocket System indicates to me a low-accuracy weapon that makes up for that inaccuracy with volume of fire (and potentially the damage dealt on each successful hit).
If you want to, you could try including the line
has_splines = 1
has_flare = 1
which seems to reduce the accuracy of the missile somewhat; however, it will also significantly alter the appearance of the weapon (specifically, you’ll see primary munitions with black trails, and all the submunitions will not have any trails visible).
It does look kind of neat, but might not be what you wanted for your weapon. This makes the missile behave more like the cruiser rockets, though not to the extremes of inaccuracy to which those seem to strive. It also gives the impression of a less accurate weapon because the paths taken by each munition are more erratic, even though a large number of the missiles still hit.