Poliwrath with Mud Shot and Hydro Pump would be the best counter for the great Tyranitar?
Maybe Poliwrath could be to Tyranitar as Lapras is now to Dragonite.
Answers
Machamp is a terrible Pokémon. There are dozen other Pokémon that are not fighting type and still do better against Pokémon that are weak to fighting.
Vaporeon will surely be stronger against Tyranitar than Machamp or Poliwrath. I don't understand your reasoning, why do you think Poliwrath would be stronger than Vaporeon? Both will do 1.25x damage against Tyranitar.
Vaporeon will do better damage but won't resist Tyranitar's main attacks which would be dark/rock types - both of which are resisted by Poliwrath's fighting type. So unless Niantic gives Tyranitar the "Hitmonchan treatment" and give him elemental punch moves, Poliwrath is a good option of having an offensive pokemon while resisting Tyrantar's moves.
I totally agree about Machamp, it has really disastrous moves, but Poliwrat has good base stats and do 1.25x damage with MS and HP (MS is good even the lack of STAB) and besides considering the possible moves (dark and rock) for Tyranitar, I think Poliwrat will have resistance of 0.8x thanks to fighting typing
Vaporean would still be better than poliwrath simply because of high bass stamina and great quick move with STAB. Since watergun is both super effective and benefits from STAB, that will make him a great offensive counter.
I also think, though machamp has crap moves, the double effectiveness plus his resist will make him that much stronger than poliwrath against tyranitar (again, only offensively). Poliwrath will only have an advantage over these two in defense, with bubble and submission move set. You get the STAB, the good defense stats, and double effectiveness with submission.
My theory is that tyranitar is not going to make that great of a defender, due to his weakness to some top tier pokemon typing. Though he'll probably be a great counter to the top 3 pokemon (dragonite, snorlax, and lapras), he still will only excel in taking them out of gyms, and not intimidating people in defense. Drop below these top 3 pokemon, and a weakness can be exploited very easily in his case.
