There is exactly 0 (zero) evidence that Maegor was actually as bad as the stories make him out to be. The Hightowers are the jews of Westeros and Maegor dismissed his barren bitch Hightower wife which made Lord Hightower seethe and cope so hard he got the maesters to smear Maegor, the citadel kikes hated Maegor because he stood up to them, Aenys was their obvious choice to back because he was a beta bitch with a shit constitution (and a bastard) so if anything the biggest mistake Maegor made was not burning Oldtown to the ground.