It seems that today the thing goes from Blues. Draztal explains the new changes to the requirements and sand ratings.
The current arena rating system allows more players in 3v3 to have a higher rating compared to 5v5 and 2v2. We are preparing an update to the game that will improve the index system of the 3v3 and 5v5 branches to allow all three to have a similar number of players capable of achieving the same indexes that can be obtained in 2v2. As a result, we are changing the equipment and personnel rating requirement for item level 239 weapons from 2200 to 2350, but note that the tooltip will continue to show the 2200 requirement until patch 3.1.2.
As a result of the previous improvements, this change will prevent an excessive number of players reaching very high rates and acquiring the highest level of weapons in the game. The increase in index requirements. is designed to keep the number of players who can obtain these Arena weapons at the same level as the players who can obtain the same type of weapons from Heroic Ulduar.
When Season 6 begins, we plan to return the Season 7 weapons to the highest rating at 2200, while ensuring that the difficulty to achieve that rating is closer than expected and is of similar difficulty for all branches. (instead of being easier for 2v2).