Ping does effect friendly fire, because in a 2v2 fight with friendly fire enabled those with lower ping will clearly have an advantage. One player will lose against a zerg anyway so there is no reason to ruin small scale combat in order to try to balance the game against zerging. BTW this is not Darkfall and there is going to be a lot less PvP going on. In PvE combat friendly fire is going to be very annoying as well and it is one of the main reasons it should not be implemented.
If a player hits his teammate constantly because of a high ping he must have so much lag he is worthless in combat anyway.
If you think FF is annoying you might want to pay more attention to who is infront of you before you press the attack button.