Squadron Size
Well, the first thing I noticed is that per usual Disney doesn't know how many pilots are in a squadron. It is 12 total, not 5. I miss the Xwing Alliance and TIE Fighter games, they stayed consistent...
Forum Discussion
I'm thinking that the 5 ship squad size is a nod to the 3 DPS, 1 tank, 1 healer rpg style.
3 fighters for dps, one bomber to tank, and the support ship for, well, not really healing, but supporting the rest of the squad with the tractor beams and auto turrets.
5 player squad for a PC game is okay. I doubt having a bigger player squad would make things more fun but maybe in the future things may change? I do not mind smaller squad just for the PC game, it makes coordination and team work necessary and not make it just a wild frag fest, but that is just my opinion.
