XII Braves really fucked up the arena battle system with the introduction of summoners. Everyone and their grandma in the top arena ranking are using the same squad combination of having 2 summoners, and a mixture of either Ronan, Lucille inqui, Faye, and Aden. And fighting a summoner vs summoner lineup, the gameplay is also very imbalanced. There is a huge advantage if you have the second turn, because you will be able to utilize all 4 out of 5 character skills on the first round, versus your opponent who will have to skip 2 char skill CD.
I'm still competitive in the arena scene, but it's becoming too boring for me now. I wanted to diversify my lineup, but there is just no way to compete at high level if you don't go along with the new meta. This new summoner meta is more cancerous than the previous archer cancer. Devs should do something about it soon. I hope they are listening to the community and do something about it ASAP.