I am in no way an expert in this so you could probably treat my opinion on the following as useless, yet here I go anyway
The way DLCs were approached seems not well thought through. In my humble opinion, dlc content should primarily be cosmetics - yeah we got a paint DLC, but I think it could and should have been handled differently, e.g.:
Have several paint DLCs, maybe one for each ship or paint style. E.g. "trincomalee paint dlc" which grants all paints on the trinc, or "brest harbor dlc" which grants brest harbor scheme on all ships. Once the ship is traded, captured in battle or sold, the ship would lose its paint status unless the new owner also got the DLCs.
Cosmetic Content should be pricey while actual ships, IMO, should be lower in price.
The best solution for ship dlcs would be for them to be just reskins of ships that are already ingame, with the same or very similar hard stats - the rättvisan seems to somewhat fullfil that, comparing with the aggie. But the requin on the other hand is super unique and its not possible to get a similar vessel. but that would probably not be possible to handle with the small dev size, and given the costs to develop a new ship.