If I understand it the theory is that a 7 man table is less fun so it would be split into a pair of 3 man tables + pregen with 1 player becoming GM.
Does the campaign seriously believe that 3 players + pregen is more fun than a 7 man table?
Leave the staff and players the flexibility to do what is needed. One of the best rules add to this campaign was the 7 man table. It makes it far easier to seat tables with the correct APL.