It occurs to me that warlord, captain, and marshal make great ranks or titles for leaders of organizations, but poor class names. They don't describe abilities. The class names wizard, fighter, cleric, or rogue describe what that chacter can do, and they do so without connotations of experience or morality. Warlord's connotations bug me. I could see:
Warlord as a leader of an evil or militaristic organization.
Marshal as the leader of a law enforcement organization or as a solo enforcer.
Captain as the leader of a mercenary organization.
Knight is a word that I'm warming up to for the class. Knight has its own connotations, but I think it could be a great way to describe the abilities of the warlord, and it just seems like a better class name. I can envision D&D characters talking about knights the same way they speak of wizards, fighters, rogues, and clerics...not warlords so much.