What other water types do you use and is powered up besides vaporeon?
I use my golduck with wg/hp and slowbro with wg/psy.
Edit: forgot to mention i also have an omastar with wg/hp
Answers
I have maxed out my Poliwrath with Bubble+HP and at 2058 CP he's a surprisingly great defender for me.
For attacking, I have given some powering up to my Starmie (WG+HP) and Tentacruel (PJ+HP), and they're both pretty fun. I also often use Seadra for training.
I'm yet to get a Golduck, Blastoise or Slowbro with good Water type movesets though.
Poliwrath is still a great defender, the only thing that people don't like about it is the low CP. In some areas it's hard to get into gym with anything lower than 2700 CP Pokémon. In my town however, 2,1k Poliwrath will be somewhere in the middle and is perfectly usable. In terms of raw damage output as a defender, Poliwrath is the 7th best Pokémon in the game. After Snorlax, Lapras, Dragonite, Rhydon, Vaporeon and Exeggutor.