The hard thing is determining who exactly gets the Commander skill. How about it being something voted on by the community, then a dev can tinker with that players character a bit. Commanders really need to be people that the community want to follow rather than someone who just shouts the loudest or sets a particular build type.
Another way is making the skill extremely expensive in the market, so only people who want it the most (or whole clans) can sub the cost. Leveling up clans is another idea, like the ones that collectively win the most rounds (who could then designate 1 member as a commander). Thats tricky too, since its hard to determine if a clan simply has a lot of members or if they work well as a team