yeah, we know Lanius follows only the man and couldn't care less about the vision, and we know Vulpes follows both equally rabidly. Lucius is more of a dark horse. I always had the impression he was thoughtful though, so probably man and vision imho.
There's a thing somewhere in-game about him commanding a lot of respect and having the charisma to keep control of the Praetorian Guard even though he is getting old and could be beaten in 1:1 combat by another guard (their method of promotion).
Anyway I'm gonna go kill Caesar again and listen more closely to what Boone says ;)