I haven't seen DS9 in so long--unfortunately I totally don't remember what that is! But I totallly agree with everything you're saying here--I think that's definitely the way it seems to work. It's not that the two are always battling each other to a stalemate and that's how they balance each other, it's more like they do both think they're mostly working towards similar goals and feel the need for each other even if they don't always put it in those terms.

I don't know XMen comics that well but from what I've read that sounds exactly like what CX is like. That there's definitely times where he'll keep secrets or do wildly questionable things in secret.