It would be nice to have less holes in my boat.
If ever I was to start from scratch I would have a composting head and my sink would drain above the water line like my bilge pump.
Raw water intake for cooling the engine and prop shaft would be the only through hulls.
Maybe someone will invent a shaft log that does double duty as a stuffing box and a sea water intake for the engine (Mainesail...here is your get rich quick scheme
My depth transducer would shoot through the hull and I would skip the silly paddle wheel for speed through the water and just use speed over ground via GPS.