Balancing the kingdoms is one thing, and the other is that the mode doesn't seem to be about being the "captain" as much as I would hope.
For example, we totally lack the option to transfer troops like in the SP. Why can't we divide our unit into two, or three, or however we wish. This would add some sort of strategic thinking into the game.
Secondly, there should be some sort of punishment for dying as the captain. It would make players wage their choices, and not rush into things head on. In this mode you should be careful not to die as a captain. Now if you die you can just take control over one of your soldiers, without any drawbacks, like nothing happened, oh but something did happen and in my opinion, the player that dies should suffer some penelty.
What I mean is that this mode should be much more about leading than it is now. I'm not saying that in current state it's bad, but it could be better.
But i know that devs got a lot on their hands right now, and it's not really the time to bother them with that, because as we know the game needs a lot of work anyway. And I realy think that they probably have a lot of changes already planned for the captain mode, but they simply do not have the time to work on them. In the meantime the captain mode is still rather enjoyable, so that's nice.