If you want to fix BG, its both easy and possibly impossible (Due to limits on what vivi can do to the code)
All you need to do is randomly allocate those that register to a side rather than have RG and FK
That way there is no logging alts on the other side, if 30 fk want to go and no rg its still a 15 a side bg, so "boycotting by one side will do nothing. There is no we only go if we have the perfect team.....
Also there would be a point to people registering when their faction doesn't have their "OP" people on as they could still get win rewards.
Keep AK as rg v fk otherwise random allocation is the way to get more in BG's