ANBU is more of a branch and is no longer as linear as genin-chunin-jounin. . i think jounin=anbu=special police. ANBU, They specialise in only killing. Jounin's, aside by being strong, require social skills in order to teach, inspire and lead. Special police, like sasuke's father, need to be as strong to kick deliquent ass
while i'm at it, sannin=hokage in terms of strength, its just that the sannin dont have executive powers
well, at least thats my opinion
"Killing for peace is like screwing for virginity."