With every Path of Exile league, the designers take the time to dissect the overall balance of classes found throughout the game in various permutations, and Betrayal is no exception to this. It is an exception to any pretense of playstyle balance, though, as the class breakdown overwhelmingly favors casters over melee characters and more robust characters over the more fragile sorts. This just is not the season for character types that mitigate damage by killing things quickly, it seems.
While Elementalists don’t dominate every single list, they’re more than 10% of the population at every tier of play and only fall below 15% in the hardcore-only 90+ category. This may indicate that a bit more tuning is needed, or perhaps it just indicates that the Betrayal League really rewards some good old-fashioned magical artillery. Take a look at the full breakdown of stats on the official site.Source: Official Site; thanks to Veldan for the tip!