OP here, just poking in for a response to "you should have 2 melee DPS because reasons" arguments.

In terms of min maxing for teams trying to get world first, two melee is probably ideal. This topic isn't about that.

Not all teams care about world firsts. Some teams are just getting started, and their FC happened to have three ranged DPS players so that's what they use. Up until this change was announced, there was no reason this team was "invalid" or "unbalanced"; with a little extra gear and practice, they could overcome the slightly lower DPS output of their chosen party makeup without undue problems. For these kind of beginner teams, limit break is the difference between getting an A2 kill or having to grind for another couple of weeks to squeak out the DPS.

Keeping a new static together is hard, I know from being my team's raid leader. This kind of arbitrary enforcement of the dev's ideal party makes forming teams even harder, which isn't what our community needs.