Change the game by all means, anyway you wish but don't change it for existing worlds. That would test your theory. However, my feeling which I can't prove one way or the other, is that a change that removes the incentive to help other alliances to the centre and moves those that get there to the edge of the world would lose those players from the world instead. Again, without evidence, I feel that they will be the ones that invest cash into the game as they stay in the centre fighting to maintain their dominance.