I think missiles may still be underperforming. Here is my justification:
The combat equation is given
here.
Consider a hypothetical engagement between two ship wings. 1000 Undines engage 1568 Minotaurs. These wings cost the same supply-chain-inclusive WUs to build (in practice the Undines are actually more expensive because the Minotaurs have a higher halfLife)
Minotaurs have 64 attack, 160 defense
Undines have 160 attack, 320, and 0.1 AoE which I am not considering (an unquantifiable bonus to the Undines)
I am ignoring range, but Undines outrange Minotaurs by 5Mm (a 2nd unquantifable bonus to the Undines.)
Minotaurs have a delta-V advantage, which at best can negate the unquantifiable range bonus.
Based on the combat equation, we would expect the Undines to kill a maximum of 200 minotaurs in the first volley while the Minotaurs will kill a maximum~68 Undines in the first volley, with the ratio of WUs destroyed favoring the Undines.
Since this is just the first volley and Undines are destroying Minotaur WUs faster than the Minotaurs are destroying Undine WUs, each subsequent combat round should be more in the Undines' favor, a 3rd unquantifiable bonus! Combat should end with the Minotaurs destroyed and at least 54% of the Undines surviving, probably more.
I set up a test battle between Undines and Minotaurs at supply-chain-inclusive cost parity. There were 6 wings each.
47% of the Undines survived and (a couple hundred Minotaurs also made it out alive survived)
A missile-armed ship which has a range AND an AoE bonus (against a unit with high ships/cell count!) AND a combat round advantage bonus from fighting a weaker adversary underperformed what would be expected of it (based on the equation). I don't know if this is in the margin of error imposed by jittering, but I suspect some other factor may be at work.
This is completely independent of any discussion of whether Undines are appropriately costed, etc.