http://halo.wikia.com/wiki/Specialization
Rogue
In recent Halo games, when your Spartan is zoomed in and is shot, it zooms out. With the Rogue’s stability mod, you have the ability to stay scoped in, even when being shot at.
Being kicked out of zoom when being shot at is no longer there in Halo 4 no matter what Spec you are so that makes Rogue useless. What use is Rogue then?