List of things I'd like to see

Playable Fiddle, Lute, and Baby Grand Piano (Galleon-only)

More tattoos, scars, and curses (specifically an anchor tattoo, any kinds of new scars, and barnacle-based and maybe even Lovecraft-themed undersea curses)

Wheelbarrows for hauling multiple chests (would need to attach it to a rowboat)

Using gear from ladders (like the telescope)

Dual-wielding for one-handed skulls/artifacts/keys