HS takes a back seat to anything on the GCD if rage is an issue. I'm not entirely sure what situation you are referring to when you're suggesting dropping Devastate for HS - there's none that I know of where that would make any sense.
Devastate is typically used once, rarely twice between Shield Slams. Out of the three rage-reducing talents, Puncture thus covers the smallest section of rage cost and is in that light already very weak. Considering that we're in near-infinite rage at most times, it becomes even more lackluster.