>>22488509No, because Sand Stream was originally exclusive to Tyranitar, and because Tyranitar doesn't have STAB Earthquake and reliable recovery, and because both Tyranitar and Abomasnow are tied for most weaknesses of any Pokemon in the game, and because Hippowdon isn't normally a Rock-type.
And because Tyranitar is my favorite Pokemon.
Seriously though, giving (Mega) Hippowdon a Rock subtyping with none of the weaknesses would be a pain in the ass. You now have a bulky Ground-type with STAB EdgeQuake, resistances to Normal, Fire, and Flying, reliable recovery in Slack Off, only three weaknesses, and effectively 108/118/117-132 base defenses before factoring in Mega bonuses. Oh, and it also negates Leftovers recovery on most opponents. It would be a massive pain in the ass on Stall. At least Tyranitar still dies to Fighting-types, powerful Fairy moves, and U-turn spam; super-Sand Sp.Def Hippowdon isn't even OHKOed by Specs Keldeo's Hydro Pump.
>>22488718Why not both?
