The arena will change again like it has many times. You're chasing ranks, that's why it's no fun to you. You can't say one character broke the arena and then 6 months later say someone else broke it and so on. In 6 to 12 months there will be a change just like 1 year ago, 2 years ago and 3 years ago.
If you're stressed that much about top 50 then maybe it's time to take a step back and work on other toons that need attention. Its a fact that if you chase the ranks then you best be prepared for a battle. 50 people is not a lot of people, just wait for the 5 year mark when even more players start to join and rank up. Every year that goes by the game will get harder and harder as more context comes in.
Pick and choose your battles wisely as the game will only get harder as more context shoes up. As more toons come even more off the wall squads will show up as well.