I have no hard evidence, but whenever I see specialists who focus on specific map types, they nearly all have very high rankings, and sure enough in the token instances in which you join the map, you find yourself usually beaten as you're navigating an unknown map type with obscure rules and formatting or win conditions and they already know the optimal approach
i could be mistaken, but it feels like we're getting very skewered rankings as a result of this, the equivalent of where some bughouse chess player in central park would have a higher FIDE than Magnus Carlsen
i realize this isn't really a problem, if people want to farm elo in niche formats they are free to do so, or those who just prefer those formats can enjoy the benefits, but i strongly feel like we'd have a much better experience here without the incentive to play weird maps and rules in order to push small advantages and where elo wasn't calculated in those formats, or was calculated for a different pool, ie everyone has normal and alt rankings