Teambuilding as it is right now is too restrictive, encouraging a meta of 8 illuvials 17 augments and a rock-paper-scissor effect.
If we had just 2 more cards per team, there would be more room for skill and adaptability in the game and make it more fun both to play and watch.
I think we all always agreed on the fact that Arena should be skill-based. This change aims to remove some of rock-paper-scissor effect to empower players again on their wins or losses.
Obviously, this change alone won't be enough to solve the current issues, but it is a step in the right direction.