The Meta Carousel

Does this actually exist? I was wondering if buffs and nerfs between classes are actually a cyclical thing, to where one class (currently it seems to be mages) overpower the rest of them, only to be nerfed when people get sick enough of them and another takes its place. Tanks, bruisers, enchanters, marksmen, assassins, mages and others... is it at random that one rises above the rest, or is it more of a naturally cyclical pattern where one class has to wait four or five metas until they're on top again?