out of all the half breeds only one of them is a mary sue.
sure rexxar and garona are bad arses but they are no different than any of the other bad arses in warcraft.
besides me'dan half races are shown to just be normal people other than some slight differences.
garona is described as prettier and more human like
rexxar is bigger than normal orcs
arator hasnt been seen to do much yet but so far he just looks like a normal paladin with pointy ears
lantresor is no more badarse than all the other blademasters.
would me'dan be any less of a mary sue if his mom was some random human? he would still have all the power from his father and grandmother
he would still be the son of one of the most powerful beings on azeroth who had been possessed by the strongest being in the universe.
having green skin and a bumpy forehead didnt make me'dan more of a weirdo