If the Game is going to be open World, There should be 5 or less Quests, For Monsters who can't go on Land and/or Hate fighting on Land like Abyssal Lagiacrus, Ceadeus, Plesoith, etc 

Make a Exclusive Underwater Arena for it via a Event Quest

#MHWilds 
#MHWs 
#モンハンワイルズ
#MHWilds #MHWs #モンハンワイルズ