An easy solution to this is to add a lvl req for quest weapons. That way Gree will be able to make sure minis cant do the "kill mobs quests" but still give out weapons for players just playing the game as it is intended. They could do the same thing with units gained from guild events. To be able to use it in your army you have to be a certain level. That would kill the minis and make players want to level again.
Right now they see a problem and "fix" it by making the game very unfair and almost unplayable for new players.