Too physically inclined. Go special with Tyranitar, please.
Tyranitar, Modest (+SAtk, -Atk)
Item: Choice Specs
-Dark Pulse
-Thunderbolt
-Ice Beam
-Flamethrower
I'll leave the EVs to the professionals :x
Movesets seem fine, but this team has too much trouble with Ice Beam + Surf. Fighting is a problem too. And so is Grass. To make it short, this team has too many shared weaknesses.
You could add in a Steel type to replace Rhyperior. That way, you can reduce the damage taken from Water moves. Don't limit yourself to Rock and Ground types. Scizor, Lucario, Skarmory... all can fit better with this team, reducing the major Grass + Water weak this team has. Luke can also serve as a special sweeper which this team lacks.
You can also consider Cacturne. He is immune to Sandstorm (thanks to Sand Veil) and reduces your team's major weaknesses. Or any Pokemon with Leftovers could fit in as well, as Leftovers would counterbalance the Sandstorm effect. A "shining" example is Milotic.
You could also use Hippowdon as a lead. That way, Fighting moves don't have so much fun if you use Tyranitar.. But Hippowdon is a physical Pokemon, so you'll need a special sweeper.
Regirock is a good option you can consider. He already has a 200 base Def and 100 base SDef, and in Sandstorm his SDef would be boosted by x1.5 (IIRC), making him a tough Pokemon. However, his Atk is outclassed by all your original team.
