Salac Berry, as well as Custap, Liechi and Petaya, are all currently unreleased, thus making them illegal in standard play. Moreover, the most time-tested method of abusing such berries, Sub-Boosting sets, mean that Poliwrath will be limited to only two attacks, meaning he inevitably walled by the corresponding poke indefinitely (Fighting Move+Water Move=Jellicent/Dnite/Slowbro, Fighting Move+Ice Punch=Jellicent/Slowbro, etc.). Thus, once it's released it might get a mention, but more often than not I feel like Lefties deserves the slot.
As far as the OU metagame is concerned, I agree with Meow in that the most noteworthy set Poliwrath can offer is a Belly Drum set, being the only SS poke with access to Belly Drum. Perhaps something along the lines of:
Poliwrath (M) @ Leftovers/Lum Berry
Trait: Swift Swim
EVs: 60 HP / 252 Atk / 196 Spd
Adamant Nature (+Atk, -SAtk)
- Brick Break
- Waterfall/Ice Punch
- Belly Drum
- Rock Slide/Ice Punch/Encore
Encore seems somewhat odd, especially after mentioning his limits as far as coverage is concerned, but should you be able to clear out these threats Poli can pretty effectively sweep late-game with only two attacks. Moreover, an Encore off a 450 speed poke could allow you the turn you need to set up your Belly Drum, as your opponent would either have to switch out or continue setting up.
He does indeed have some cool options defensively, having adequate bulk on both ends of the spectrum, backed by some neat resists, but i feel like there are simply some better options when it comes to bulky waters :/ He does have Bulk Up and Circle Throw, but Scrafty, and to a lesser extent Throh, also have the capacity to Bulk Up and phaze, each having aspects that better insure their longevity.