I think a cool thing to add to a later update would be sicknesses you can get like Scurvy or Laws Sickness that can make doctors more useful overall and want to be chosen more [I thought it would bring some cool aspects to the mod]
Scurvy could be given from being in an ocean biome for 3 Minecraft days straight and cured by eating Tangerines (Most famous Pirate illness)
Uncurable Disease very rare would be 0.01% chance of given each Minecraft day and once you have the effect it'll be given for a few minutes before you (Hiruluk and Gol D. Roger had this, maybe not the same but similar)
Amber Lead Syndrome could be given by being near a new block called amber lead which would be a nice shiny color to bring attention, could most likely only be cured by healing devil fruits like Ope, Chiyu, Tori Phoenix (Law had this illness)
Mummy a craftable weapon that gives players/npc green spots and gives them poison, weakness, and slowness effects. Cured by an attack by the doctor fighting style (Wano Arc)
Ice Oni a craftable weapon that gives players/npc ice spots and gives them poison, weakness, and slowness effects until the second stage occurs making them zombie like ice monsters. Cured by an attack by the doctor fighting style (Onigashima Arc)
Also add to this if anyone has good ideas to the suggestion please. ✌