I'd be interested but it would need to be completely different to what we are seeing recently. For me at least, everything we have so far in the game I consider to be early game or experimental. The game would need to stop focusing and catering to new players and casual players and stop creating mediocre shallow content. The game needs to be better organized and have better scaling, so as to provide all players a way to learn and master the mechanics so that when players level in rep, voyages start to challenge them in exciting ways that not only tests them, but provide them with twists to continue playing through the narrative of voyages as well as expose them to greater epic combat situations (Like fighting on top of a spire, ontop or inside a moving giant platform, a dark cave, wrecked ship, a man of war, a town, a whirlpool, etxc . For their to be a sequel, a few things would need to be worked out first. I can brake those things down into specific components listed below:
Treasure
Treasure would need too be better organized, with themes not being interchangeable (That includes Athena voyages being the sole provider of phantom treasure, goes well with the theme and it's higher quality treasure than their counterparts). Treasure rewards would need to be organized with higher difficulty challenges or longer (multi parts) voyages providing more rare and higher quantity gold. Furthermore, no voyages should provide instantaneous gold upon completion, all gold should be received from selling treasure or opening chests. This is to say that instant gold rewards are extremely restrictive.
Weapons and tools
More variety of weapons and tools wether they may be an actual flare gun, a swing shot, a sluggish hand cannon, etc...
Furthermore weapons and tools should be more useful for combat, traversal, platforming, and puzzle solving. Examples: such as Lanterns should be used to see in the dark or gain different colors to open different lit areas, to see hidden mirage or dark pathways, and to light more trigger torches (perhaps with corresponding different colors for more complex puzzles). Instruments should be used to actually open gates through corresponding rhythm puzzles, emotes used for Simon says type of puzzles. Weapons to solve solve "bulls eye" activating mechanism for doors, gates, or even bosses (Hitting the bulls eye on an environmental object in the boss arena to weaken said boss or make them vulnerable).
Enemies
This includes more varied enemy and boss types including varied enemy abilities. So far we have the same generic abilities for most enemies and bosses, for a sequel there must be enemies with smarter AI, enemies abilities such drinking grog and spew flames out with a torch or phantoms that can hover around, or enemies that can transition between land and water or even board ships. Furthermore, this includes more specialized enemies showing up in voyages at higher difficulties, not simply the same enemy behaving like a meat tank.
Voyages
Voyages should be more complex and entertaining in terms of story telling, platforming, exploration, and combat. Each sub goal or challenge completed should provide a small amount of treasure. (The example for this is too long, I have an idea on how they should work in the first topic post I ever created, just go there, on my profile, to get an idea of what I mean if it interests you). Furthermore, this includes a better system for voyages, with more complex voyages scaling with reputation level, and sub goals rewarding more and rarer treasure as one progresses through it. Voyage distance length would need to be reduced. Merchant alliance and the hunters call (fishing) should be merged together. End game would need to actually have meaningful content and epic lore, not just a copy and paste rehash combo mix of what is already in the game but with boosted health for enemies.
Cosmetics
More advanced ship designs, with ability to customize railings, masts, decks per level, ship lanterns, captains quarters (Beds rugs, open/closing doors, table, chair, etc), back of the ship balcony area or back of the ship design, etc. Overall the game should have less focus on purchasable cosmetics or microtransaction stores.
Exploits
All exploits would need to be removed. Sword lunging exploit should be the normal substitution to regular lunging, no portal hopping, Red Sea dumping, faster bucketing, or shoveling, or moon jumping, or quick weapon swap, or silent ladder climbing, no tricks. Play fare and transparent, either learn the mechanics or fail type of deal.