It all apparently comes down to squad sizing. The PC, Xbox One, and PlayStation 4 versions of the game are designed to support 64 players right out of the box. If you bump on the squad size (say, 6 squads per side with 5 players per squad) you arrive at 30 with one squad with 2 players. At 70, you could have 7 squads per side with 7 players in each, but that could change to perhaps 6 players in each. In the end, it is finding the right balance and going with what makes the most sense, we would think.
Large maps with massive amounts of players could present some interesting battles. We have seen the large player sizes on the PC be a big hit, so it does stand to reason that it could also be quite popular for the consoles.