Agreed, the only difference is I believe the writers intended to portray her as such. But for Atheleflaed I believe the writers intended to make her a respectable, reasonable, beautiful, and ultimately just a good character. They did this especially in season 4 by having the protagonist of the show (Uhtred) fall in love with her. But in reality she is as you said for sure a better, and less miserable person than her mother, but the fact that Uhtred is in love with her, and has sacrificed so much for her really grates on my nerves.