I dont like Random mirror. No one can prepare for that. I do like "set mirror" though. Can change the set civ for different rounds. I also liked the idea from Viper vs Hera showmatch by Nili. Have 2 games where each player chooses the mirror civ once.Also, even the meta is not developped yet we now that it will be by the end of the tournament.
But I like the idea of random mirror, once in a while. I think I haven't still seen a pro playing tatars