Thoughts after playing 0.13:
With the inclusion of the ship minigame, the MC's stats and the bounty posters the game is on track to become than a simple VN. Editted AI-Art is fine with me for parody games as long as the edits sort out mistakes of AI. Keeps cost low and speeds up the process. I haven't seen every lewd scene since I couldn't be bothered with the current point system, but the Alvida scenes looked fine to me.
With 5 chars who joined the crew and 3 side-chars, I'd say the game has advanced enough to give people their need for the lewds and visuals.
In my opinion what needs to follow is filling the game with more game mechanics and connecting them.
In the current state all one needs to play through is money to buy story items and the MC's strength stat for the battles.
The crew is irrelevant for progress right now, but most of the lewd is tied to a point system with them.
So if lewds are important to the player, instead of playing the game, one just choses the same options again and again until the scenes are unlocked. With 5 characters already, that is a lot of just clicking and not playing. It also makes progression with a girl not very immersive and could be a source of fatigue for the player.
So I suggest to add more game mechanics and connect the various systems to have a smoother progression.
For example the ship minigame. Shots by the enemies can miss, this could be attributed to Nami's navigation skills, or boarding the enemy ship could give tribute to Yamato since she was introduced as the fighter of the crew. Praising them for their contributions could be a source of naturally leveling their lewd stats or even give them unique stats that improve certain chances in those minigames. Robin could search for hidden treasures on the ships with her devil fruit or something. Surely the enemies don't have just gold, money and cannonballs and she could get creditted for finding it.
I understand that it can get very complex the more characters you plan to let join the crew.
Some could be used for different duties like Perona for cooking, since you need to heal after battles, cooking/nursing would be used frequently enogh to be worth it. But with Yamato and Boa you pretty much already have an overlap of what the character's main trait (according to official One Piece lore at least), which is strength. Maybe introducing a RPG like class system fitting for a ship crew might help here to reduce the burden on coming up with different mechanics for every single crewmate. A fighter class for Yamato and Boa would make sense and instead of chosing for every battle who participates, we have a simple menu to decide which is "on duty" to get level up points, to make it easier for the player to manage this.
If one really wanted to go excessive this game provides the structure to mimic something like those old maid-raising games, by assigning them different duties/schedules on the ship. But don't bite more than you can chew. Some simple things like training in the presence of girls to increase their lust is also feasable enough to passively raise their disconnected lewd-stats.
Anyway, I wish you success and a lot of fun on your journey with the game.