Passives please?

I'm levelling a Prot warrior. Shield Slam does close to no damage. If I was a new player, I would be like "Why does this
do no damage?" and probably just ditch it. If I was to look at a guide, I would see things like "Hits very hard, use
whenever it is ready". I would be even more confused, because that is NOT what it actually does for me, and I can't
see anything in game that would ever change that. So, I assume there's some hidden passive somewhere that makes it
worth hitting that button. How is a new player supposed to make sense of his spec-defining ability doing no damage?
You really need to reconsider showing passives at least SOMEWHERE in game, instead of completely hiding them
Some damage examples for Shield Slam and Revenge at level 40-43, only counting 1 target for Revenge:
Revenge: 700 non-crit, 1.5k crit. Shield Slam: 50 non-crit, 180 crit with Sword 'n Board
Another comparison: I used 22 Heroic Strikes during a Dire Maul run, they did the same damage as 88 Shield Slams