Oh God, I make a call for debate on the merits of feudalism, and you people go off on another nerd tangent about crossbows and religions. See, this is why we can't have nice discussions, always nerding it up about off-topic crap.
I don't know what all this talk of monarchs and slavery is. Who says a feudal economy has to be unfair and repressive? Everybody gives up a portion of their growings to the local magistrate, who can be elected by the people for all I care, and in exchange the magistrate uses the crops to pays his laborers to make arms and roads for his armies to protect the growers from marauding bandits and other lords. You can even apply it to realms besides agriculture, like indie programming or cybernetics research, as long as you can find some robots or slaves or robot slaves to make all the food. I mean, it's so simple it has to be good.
Of course, the whole thing falls apart when you let those damn merchants and guildsmen in. Fucking guildsmen, bargaining in groups for profitable exchange and market control instead of taking what they're given. I'm the king dammit, I don't have to pay you at all if I don't want to; every shilling that leaves my hand is a gift by divine right, and you'll be thankful for it, dammit.