Actually your post sounds very unrealistic!! Now I need to learn the definition of being realistic from u I guess
coming to the point what made you think he is unrealistic?? Just because he is sensible,matured and at the same time a crazy lover certainly will not make him unrealistic!! There are people in the world who possess all these qualities!! He did have flaws initially,which over the time he has come over it!! U see perfection cannot be achieved overnight it takes time and also if you see he has grown with the time!! When one is young they possess many flaws but as the time passes by you learn from your previous mistakes and try moving towards perfection by rectifying them!! This is not hypothetical but it is the truth!! So this development can only be seen in Swayam,in the whole of other D3 characters. He has over the time grown as an individual.So before questioning swayam reality,better get through the whole D3 which might help you in knowing his swayam better way!!
P.S I believe he is more realistic than all prince charming sorts u see!!ya right now in D3 other than swayam,Sharon can be considered as a realistic character too!!