>>22222013water absorbing hypnosis bot with subpunch tacked on is a gimmicky way to use him
you could run a bulk-up swift swim set with a rain team, the added benefit being that it gets tanky as well as being able to hit hard so once rain runs out it can still stick around and throw out more hits.
you could also run him as a straight water absorb tank with scald.
poliwrath's stats are just too normally distributed and it's move pool is too small to be considered useful over his many many many competitors