That's the same in RTW CBR.

Try this:

Use a cata silver weapon/defence against a Triarii golden weapon bronze defence. The cata will lose. Now try it again with the cata wedged, it will win. Why? Because it will break the Triarii's formation..

Try it with a phalanx. You can beat any phalanx unit no matter how strong is it with a normal cata if you to mess their ranks..