E-Sports work best when there is only a few per team so that you can recognise them by the player (similar to basketball) whereas in sports where you have stacks of players so for example NFL, there's only a few recognisable (to casual fans) so your quarterback and maybe a couple others.
Also, more players mean more money needed for the gear/ accommodation/ travel all of that which when you have a team of at least 24 plus support staff It would end with only the 2 or 3 richest teams being successful as other teams couldn't afford to send their teams to tournaments.
so large scale stuff would never work. Although if they were to set it up where the teams play as squads so 4 or 5 per team and then have multiple different teams, together to form one side verse another where the squads are working together to beat the other team but also trying to beat the other squads at the same team it could work. but might end up being confusing to the viewer so Battlefield doesn't really work for e-sports