When your side is losing you should get radically more LP for doing plexes and whatanot.
Abandon tier system as it is. It only penalizes people who actually work for your faction and donate LP and stuff. I have no idea how to replace it, but yeah.
a) This would help keeping sides balanced so people do not just pack on winning side.
b) This would also make sense since your faction should be more thankful when they have hard time.
As it is currently no one wants to go play on faction that has tier 1 level unless you just want to roleplay (lel).