Titanfall's Lead Designer Talks Numbers
In a normal FPS multiplayer game you would be forgiven for thinking that a 12 person match would mean slower gameplay, with each team sprinting around looking for the other team. However, the thing to remember with Titanfall is that you're not just a little human running around, you're also a massive noisy mech. This means that it shouldn't take too much in the way of checking your corners to find the next person to shoot.
"The higher the player count, the more uncomfortable the game gets," Hendry told Polygon. "Unlike in most games where you can sit there and guard the two ways in, in Titanfall the guy can come in through the window right behind you, he can come from the window to your left, he can come from straight ahead, he can come in from the stairway and he can come in from the doorway, or whatever. Essentially there are five directions you can get killed from and the higher that player count, the more likely you are to get killed from behind and the more difficult it is to kind of manage your surroundings."
Remember that aside from other human players Titanfall's multiplayer will also have up to 50 AI running around trying to kill eachother, and you, all the time. If you take the number of human players up, when will you ever get time to smash stuff with your mech?
Hendry said that Respawn tested Titanfall's multiplayer with as little as two players and as many as twelve before settling on six as being best in the ratio of fun against chaos. Anyone who's spawned in Battlefield 4 and been killed before they've even taken a step will know the agony of just too much chaos. Pushing for player numbers just so you can write "64-player multiplayer!" on the box without taking the actual gameplay into consideration is a surefire way for any studio to shoot themselves in the foot. When it's the first game of what could become a major franchise, you're losing the whole leg.
The maximum player count isn't really an issue. Sure, if you were expecting more and had your hopes pinned on throwing random grenades and getting kills I understand your disappointment. If you think multiplayer games need massive player counts per map to be fun, then the developers are aiming to make a completely different game than what you are looking for.
Of course, my support all depends on the honesty of the decision. If it really is about the fun and playability then I'm right behind you Respawn. Stick to making a good game. If it turns out that in reality the "next-gen" consoles can't handle all those metal bits clanking around and so you're shrinking the multiplayer, I hate you.