Since some countries (like somalia) don't have enough players of a high rank to become kings on the current system (plus being a merchant means being non-violent, so attacking NPCs even is not great), how about we install a system in which there is a line of royalty like system. Based on the ranks of the current citizens, if one is higher than all others, then he/she will become king in the next update(s) until someone were of the same rank. If all are citizens and all have the same influence, then there will be no king for that country. When we have multiple people of the same rank then we resort to influence to determine kings. This would benefit those nations who have a smaller base of people. It would also provide a worthy goal for a person of small rank and/or influence.

The current system is fine, there can't always be a king, you just have to work up for it. If that was the way it was, then everyone could be a king.