I already suggested it somewhere else - make a poll in the forum to decide which volunteers for being commander enjoy the highest respect and faith of the community, and once the vote is set those on top of the list (about 10 to 20 players, I would say) get a special status on the servers, similar to admins (I never was admin, but I suppose you are automatically admin if you log in to a server with your character, or do you need to log in extra?), with having access to some nice commander tools.
Whenever there are two or more commanders, both will be autobalanced into different teams, and the commander tools will be unlocked. If there is only one commander he can't use his abilities, as it would be unfair for the team without commander. If there are more than two commanders, a ranking system will decide, according to the result of the forum poll.
To encourage players of following those commands you could give a small experience or gold reward, e.g. reaching a flag position (once per tick possible, no abuse by moving the flag a meter every second, farming money and experience).
I just got the funny idea that players could also get small rewards for every killed enemy (5xp, 2gold, or perhaps 0.01 more on multiplier?) within a certain range (50m radius?) as long as they did NOT kill them, themselves. I bet this would have funny effects on player behaviour, making them support and protect the others, in the hope of helping them to kill an enemy. I don't think enemies would be sorrounded but not attacked, the greed won't go that far, but it could support more little "suqads" like a shielder at the front, followed by a two handed fighter and both supported by a pikeman and a crossbowman. If they decide to help and protect each other this squad is a damn nightmare for everyone.
If you don't want to see or hear those commands you can disable them with a key combination, similar to muting all players, but I think it is important to have it activated by default to "catch" all those casual players who are not that into tactics or community affairs at all, thus not being up to date about new features like this.
The idea with the forum vote is not ideal, but I don't see any other solution to evade any tiresome ingamevote which probably won't succeed in most cases anyway, if the engine allows votes with more than two options at all. And any other "automatic" designation will be more than suboptimal, as the personal k/d doesn't say anything about this person's tactical or at least leadership skills. Most coaches for any team based sport would perform rather bad if sent on the field (again), and many of the best tacticians in history (e.g. Napoleon) were not really strong fighters, compared so some seasoned sergeants in their armies. And yet the coaches, and not the top goal getters decide about the tactic, the generals and not the non comissioned decide about what an army will do. So the K/D-ratio is really a bad base for determining who should be commander.
The votes could be repeated regularly, and the W/L-ratios of the different commanders (when being in charge, of course) could be tracked, so after a few months there would be a hand full of accepted and capable commanders. cRPG and strategus seems to be the attempt to transfer the entire single player gameplay to multiplayer, with the only difference that there are no bots, only players. So having a commander would still fit to this, as in single player it's always someone who's commanding the rest. Especially as both determining who is the commander as well as listening to his orders is up to every single player to decide for himself.
Anyway, I am more intelligent, so I am right, there is nothing to discuss about. Period.