I've got one issue. Recruiting without using money. If you don't need cash to recruit, it might be too easy, but then again I could just make less recruits available. Hm.
You could still keep a currency - polished pebbles, or clams, like in The Flintstones

, or something similar...As long as it's a scarce. I mean, decrease the earnings to minimal and the less "money" you get, the less rectuits you'd be able to enlist.
Or, I'm not sure if it's doable though, you could link the recruiting to, say renown. I'm not sure if renown could be decreased though. I was thinking something along the line of Saxondragon's PoP honor-related-troops system, where you could recruit higher tier troops after building a knighthood order in a castle/town and each one costs you honor.