teams could still have regional broadcast groups, that are replaced when they are on a different platform. But 80% or whatever would be broadcast by the regional cast that is more familiar with the team. MLB would control those groups and then sell the rights to the other platforms (fox, hulu, amazon, etc) who would use whoever they wanted. All TV money would then go into a pool that would be divided by the teams.
The sport needs something to bring the teams closer in competitive balance. You can't have teams getting billions in TV revenue and not have some sort of salary cap.