The multiplier system is bad, valor system is bad. Obviously combining the two obviously wasn't going to improve the situation, and in fact the sum is even worse than the parts.
The reward system nearly everyone wants is xp/gold proportional to your contributions to your team, with bonuses for proximity to objectives (flags/gates/etc), winning the round, and difficulty (kill a lvl 35 in full looms as a lvl 15 in peasant gear? Big reward for you). I just don't expect anyone to go through the trouble of implementing it this late in the game.