I feel like we need a much much larger ship, at least for multiplayer. Here's why;
The large ship we already have is great, don't get me wrong. It's a decent size for everything you need, but this is only decent enough for one person. Playing with 2/3 of my friends, ships can get very crowded relatively quick, especially if we're packing up to explore a new island and need our crafting items. On multiple occasions we would accidently push each other overboard or fall off due to lack of room. Not only this, but once more players are on an island, resources are used up much quicker, therefore the option of building a boat for a crew of 1/2 is a much harder feat.
The small ship size also really silences the huge amount of creativity I know many people are capable off. So many creations I see with massive ships are hugely put off by a tiny little unrealistic hull sitting at the bottom, as the is no other choice to build these things
To defeat issues like this, I think a great idea would be a much larger ship, perhaps twice the length of the current max size, and triple the width? I know I saw a lot of suggestions for a built in hull space, which I think is a great idea. This would mean a lot of ship builds would be less messy and cluttered, especially with the current ship+building on ship small bugs.
Watching Youtube videos on the game will show you quickly just how popular the boat/ship function in the game is, and in all honesty everybody's childhood pirate loving side comes out when building said ship. I feel like a much bigger sized ship would really, really expand on this and make the game even greater!