To me they should keep the current format of a fighter having a default intro, it gives them a certain distinctive trait (The answer lies in the heart of battle, anyone?) let the custom intros only for specific matchups, there is no need to go full MK giving unique dialogues for every fight; make them short but impactful, like Ryu-Ken’s brofist or make them like a very short “Fight your rival” cutscene (for example, the last 8 seconds of Ryu-Ken’s rival cutscene could make a cool intro); I have a soft side for those special intros since they were the way i knew the relations between the characters way before understanding anything in english. With that said, literally every other aspect of the game is more important to me than this, so put them in if there’s time and money to do so.