Here is another idea that could improve the game.
In Arena usually like half the players in the list are inactive players who were demoted due to inactivity from much higher leagues.
The inactive players often have more than double the squad value as everyone else, so most active players have no chance to win against the demoted inactive players.
This prevents active players from getting promoted at a fair rate into better leagues, as they now have to beat inactive players from much higher leagues.
A solution could be to give all demoted inactive players -10% to all stats (for example) per demotion. This effect should only apply to defence. They can recover the penalties each time they get promoted, when they start to play again.
This allows all active players to get to their deserved league significantly faster and Arena will be more fun and more balanced for everyone.