Here is the list of best attackers vs Blissey (below). The only issue I see is that Poliwrath is weak to Psychic and both Blissey and Lax have the possibility of psychic primary attacks. Blissey has the possibility of having Psychic as a charge move which some argue is tough to dodge. I think all attackers are so much more of a personal preference than defenders so it is really up to your style. If you like to dodge and like his moveset then go for it. Just know that a Flareon with optimal moveset will probably outdo this Poliwrath from a pure DPS standpoint. Also, a Flareon or good ol Vaporeon may be easier to aquire and get candies for.
http://i.imgur.com/eZgN3vk.jpg
