I mentioned off-hand in last weekend's WRUP that Blizzard borked the system again, and it turns out they did -- Crygil recently announced on the forums that they are working on an in-game update that should improve the ratings system of the 3v3 and 5v5 brackets to allow players in those brackets to achieve ratings similar to what can be gained in 2v2. They are also pushing the requirement of the iLevel 239 Furious Gladiator weapons from 2200 to 2350 to prevent more mayhem because, well, it's kind of too late to take back all those iLevel 232 weapons running around now, isn't it? The good news is that Blizzard is properly rewarding the other brackets after three seasons of having 2v2 advance faster and farther in ratings. The Arena Ratings system has undergone several iterations since it was introduced so you'd have thought Blizzard fixed it somewhere along the road. Apparently they didn't.
Crygil also points out that for Season 7, Blizzard plans to revert the requirements for the highest rated Arena weapons back to 2200 but ensure that the difficulty required to get those ratings are "closer to what is intended". This means that Season 6 is just about the best season to get into Arenas because ratings come rather easily. You know how Blizzard keeps on nerfing Ulduar so more people can experience it? This is the time to try out Arenas because the new progressive ratings system feels good. Just don't get used to it too much because Blizzard is going to 'tweak' the system again for Season 7.