How is the UK (or any western monarchy today) a monarchy in the traditional sense ? When was the last time the Queen made any major politcal or economic decision for her country huh? Afaik most western monarchies are merely representational these days, but then again I don't claim to have any greater knowledge on this topic, as I'm not interested in politics.
Monarchies are frowned upon because it's almost entirely up to one person or people close to him/her (see China in the past) to decide things and if these few happen to be nutjobs the country is screwed. And just because somebody was a great leader doesn't mean his/her children are aswell, so it seems unreasonable (to me) to make the first born of that person the new leader just like that.
But ofcourse there are several advantages, like the ability to make quick and potentially risky decisions.
