How the heck is Hippowdon A Tier and Tyranitar is in B? Having any Tyranitar on your team guarantees that many A and B tier pokemon will do no damage to your team. Not to mention its weather effect turns Politoed, Abomasnow and Ninetales back into D Tier pokemon when it switches in. And it is a direct counter to an S-Tier pokemon Deoxys-D, and gives SpDef support to Terrakion. And for the most opinionated part of this post, there's no way anybody in the world can convince me that Tyranitar should be in the same tier as Xatu.
Hippowdon can not switch into the other weather starters at all. It also can't use attacks like Pursuit, Fire Blast, and Ice Beam. Hippowdon is setup bait for basically every S and A Tier mon. Hippowdon can't switch into at least 80% of S, A and B Tier pokemon at all. Seriously look at the list, it can't do ANYTHING to them.
tl'dr: Switch Tyranitar with Hippowdon. Ttar to A, Hippowdon to B
NIGMAN: JRRRR IS A SHIT
NIGMAN: HO ESLE THINK IT??