What if gold mines had a limited supply of gold. Would make end game more about killing Demigods and such AND make neutral mines VERY important.
Based off this, it would probably be better that gold mines start off with a better "rate" of gold that slows down the longer it is claimed total. Means there would be a rush for mine control and fights could center around them early game, but late game when lines are more established they would still have some use, but not game-changing so that demigod killing would be prefered.
Limited amount of gold would further encourage early rush strats, which seem overly prefered in competition already. My experience, and my friend's experience.