I would prefer the plot to be as realistic as possible but I would like the main character not to lose at the crucial moment when he has to fight for something really important like his dragon or maybe his future wife or girlfriend.
Realistic seems better but you could make him an intelligent person and when you have the impression that he is losing he turns the situation around you see what I mean?
Em i think realistic is better but you need to consider that aerys is the champion chosen by the old valyria god so yea it need to be alligned with the setting too i guess
