A "rotating" ruling class is a lot more contestable than a hereditary one. That makes it at least potentially more meritocratic. (It could also theoretically be less meritocratic, depending on how power is contended in any given case. But typically, the "hereditary" case involves battle-axes, dark intrigues and treacheries, which is the polar opposite of actual merit.)

It’s not very democratic. Someone was in the right place at the right time as much as they earned it, do they then deserve to have basically 100s of orders of magnitude more influence for their life? Just doesn’t add up.