Hello. You pretty much have a good ammount of ships for all purposes and i dare to say more capitals in ratio comparrison with other mods (and hard balanced if that was your intentions). Main issues for me would be the weapons that i must be really forced in order to use and the bad pd layouts on some of the ships.
About the ships. The aesthetics of seacreatures like hammerheds ect tend to make the ships big targets and mounts layout are consetrated in odd spots leaving range related gaps in some cases. Trying keeping balance with some extreme aesthetics design is a tough issue it seams.
Weaponry on the other hand feels incomplete. It has a good number of them but most fairly tamed. Needs 1 or 2 more damage/range weapons even if they are rare so to stand out from this mod.
Now about the faction as a whole.
Anyone could single out some shp to play and it's beutifull in aesthetics without a doubd.
If you are playing vanilla game you can use this mod to add numbers or with the intent to use it as your faction. It will be a tough and peculiar run at least.
But for heavily modded runs.. I don't think it can stand in a game without wiped out from some random npc battles. For me i feel like it would be better to spare pc performance resources on some other factions for the long run of the game as it is.
(This was my personal honest opinion since i saw you wanted feedback but by any means i do not undermine the high level of your work or the fact that most players would enjoy it as it is so i hope you don't take it the wrong way :3.)
About what else could fit in there. First thought i had was a destroyer class ship like sea turtle's shell with crazy armor with pd all around going super mario drop, spinning-ramming system and shooting down missiles and wings.. That's my mind so just ignore it XD..
PS: I guess i could do a more detailed report in ships/weapons by names but it would be like an essay and my post is already an eyemelter as it is
..