I just started trying to analyze the variance in the ladder games, but there simply isn't enough data to do so.
You can't see ladder ranks for the teams at the time they played a game, and the forum writeups for the tiers simply don't include global rankings most of the time (which are necessary to be able to compare playing a tier up or a tier below).
I looked at four or five games in Seasoned and there is a clear trend of teams 1-4~ playing down and teams 5-10~ playing up in general, with some wild variance between 4-6, but the sample size is only 6 or 7 games which is not good enough to make any kind of conclusion.
This game isn't perfect and I'm not saying it needs to be, just random scheduling of your opponent in an Elo based system with no consistency is just going to produce some "lucky" teams that get "more opportunities" to improve their rank than others. I don't know how people can argue against that, maybe you can say "I don't think it matters" but that's a completely different argument from "It's bound to even out which makes it fair". Let's just admit that it's not fair, whether you think that is okay or not is up to you. The fact that it's one big elo range where there are specific thresholds that other players get much better than you are (tiers) is a seperate wrench that only makes this problem worse. I don't know how people can argue this is a fair system.