That doesn't explain why Tyranitar is generally considered more of a pain than the dragons. From what it looks like, Tyranitar's moveset with its stats are huge, with it being able to learn Fire Fang, Ice Fang, Thunder Fang, Earthquake, Crunch, Dragon Dance, Aerial Ace (which is 2x effective vs fighting), Avalanche, Brick Break, Pursuit, and Stone Edge. Sure, fighting will be 4x effective, but if there's a trick room used beforehand, a fighting type would be no good because Tyranitar can OHKO it and be faster, and even pokemon like Dragonite would fall pretty quickly to it (if not OHKO).