I like the idea that ships are now more customizable than ever - I truly believe that this benefits gameplay and makes things more interesting and unpredictable in PvP. An Endymion is no longer just an Endymion.
But why RNG? RNG has always been and will always be game-breaking in my opinion - especially when it costs time and resources. I should be able to get a ship identical to that of my friend provided that we have the same crafter making it using the same materials.
I'd like to propose the following:
Create a set of resources that only spawns in a few locations on the map (such as Copper and Cartagena Tar).
Make it easier to get the special resources to give people an incentive to go and get them. Make use of trade missions for this; a 5-hour sail = 5 Cartagena tar.
Make the new Trims require these resources too.
Create skill-books for each trim for the crafter to learn if he wants to make it part of his ship build.
Make the skill-books purchasable from the Admiralty-store using Trademarks obtained through Trade missions.
Let the crafter choose the quality of his ship so that we always know how many upgrade-slots the ships have by using extra/special materials.
End RNG..! Bring back skill.! - Give people a reason to be crafters/traders.
By implementing this you will increase the number of ships in OW, encourage trade, encourage PvP, end monopoly on special materials and get rid of RNG