Like he just said, the fourth line. I experienced this issue as well and it let me to quit BAP because of this. Line score seems to be purely on point production. It's insanely hard to produce points playing 3-5 minutes a game with grinders as a 76 overall player. And we can't get much XP to grow with 4 minutes a game and C coach feedback score every game (no ice time to increase it). The icing on the cake is we have to spend all our energy points on our health, instead of trait points. Unplayable.
The only people not complaining about this are playing as snipers on rookie or semi-pro.