Porenn is probably the most human of them, deliberate caricatures never become someone's Sue or Stu. The main irritating difference is that every female character who gets developed either has a horrible flaw that makes them repulsive as a Sue or gets turned into a Sue. The character development in the books isn't exactly noteworthy to begin with but the female characters are always worse. When they do get a chance for growth its usually either trivial or Sue-esque. Adara's the only genuinely sympathetic character who never does this and she exists in the series strictly to let Garion and Hettar develop, her motivations are never explored besides her obsession with a homicidally-obsessed prince. If they'd broken that, by having Hettar reject her while she's wounded and thinks she's dying, as they did with Brand's son, it might be different, buts its like David Eddings didn't think he could write a decent female character so he handed them off to his wife or just wrote cliche garbage up on them.