Yep, that is what I meant. Perhaps only give soldier players the abilities to change army and participate in events and suchlike wherever the army is located.
There could also be an individual player renown system which ties into Knight renown and that into a Kings renown.
eg.
Soldier renown = his renown
Knight renown = his renown + all his soldiers renown
Kings renown = his renown + all his knights (plus the knights soldiers) renown.
This would create a kind of troop economy. Kings will want the best knights and knights will want the best soldiers, while soldiers will want the best knights to lead them to victory leading to more renown!
Just a friendly suggestion