[Olm]

I think there are definitely traits on non magic commanders that make them worthwhile. Speed is the first that comes to my mind, as I play lot of MA Man.
In CBM you have the Knight Commander of Avalon with Map Move 3. Nobody can lead an Army of Knights of Avalon as efficient as him. An independant leader would miss one mapmove and the forest survival.

And if you want to do something else than Stay behind troops you have to kit your commanders to be thugs. Give mentioned Knight Commander a Black Steel Full Plate (or a Marble Armor) a Frost Brand, a Vine Shield and a PoL and let him attack rearmost enemy together with his 20 or so superfast Knights. That squad will really deliver a punch!

Or just give him a Thunder Bow. Its cheap and useful.

I don't use lots of them, but I have always 3-5 to lead my knights. And I would even recruit them if they were cap only.