Tyranitar: OK, so this guy is a mixed attacker. He has good bulk, and get's a SpD sandstorm Boost. Because he gets that Sandstorm boost, I think you can give him some Physical defense, so he can withstand an EQ. Try this spread : 248 HP/ 68 SpA/ 128 Def/ 66 SpD/ And if you wanted you could make him Relaxed. This would make a nice Tyranitar, and He'd be pretty bulky. HOWEVER, you're almost sure to know what is coming next. I simply cannot answer this RMT with out suggesting...
Trait: Sand Stream
EVs: 252 HP/ 252 SpD/ 4 Def
I like this guy's bulk, and stalling tactics better. I've tried both sand-streamers, and I'll choose Hippowdon over Tyranitar any day. Just had to throw it out there.
Ferrothorn: I've usually found taking the time to get up spikes is a waste. It only does a bit-o damage to the poke's and doesn't hit Flying/Levitating foes anyway. This ferrothorn is best for leech seed stalling, and he usually does better in the rain. People usually find a way to fix him before he can do all of his stuff (in the sand, that is). I also believe there are better Steel Types out there. Plus, if you follow MY advice, hippo will be your staller. It looks like you want another bulky pokemon on your team, and I think I have the answer.
Trait: Clear Body
EVs: 252 HP/ 252 Atk
Nature: Adamant(+Atk, -SpA)
Tank. I do believe he is the best steel type tank in OU. You should definitely give him a try. He's SO strong. He utterly destroys Blissey. His biggest threat is a burn, in which case you can switch into Rotom-Heat if you predict it.
Starmie: I love starmie, and you have a good set (assuming you hit with hydro pump). But, why Lefties? You should definitely give him something to compliment his variety of attacks. You could give him the expert belt, seeing that he's going to have a lot of super-effective moves, or you could give him the good 'ol life orb. He's got the speed, now you just need to make him hit hard. He's not going to survive that many hits anyway.
Toxicroak: Ohiseewhatyoudidthere! Yup, it's the dry skin toxicroak, to help you with your massive water weakness. Well, you know there's another guy that's been working REALLY well in OU lately, and I'm sure you've heard of UP's great set. Oh yes, I'm talking about the legendary (not, like, LEGENDARY legendary, but he's legendary) Gastrodon!
Trait: Storm Drain
EVs: 252 HP/ 128 SpA/ 44 Def/ 84 SpD
Nature: Modest(+SpA, -Atk) or, for the more bulky type, Calm(+SpD, -Atk)
This guy is so wonderful, and once he's stockpiled, he's only really hurt by poison. I like toxicroak too, but since you said in your description that the team isn't working so well, you might as well try him out.
Landorus: Now this is new, we have HP ice! (It might just be new to me) Das Kule. It really takes care of Gliscor, if that's your problem. Being that he's Scarfed, I think it would be fine to give your Landorus a Mild nature to power up HP ice. I'm enthusiastic about this guy! ;)
Rotom-H: Finally we see rotom. He looks good, and will be unaffected by those burns that can hurt your physical attackers on this team. Stops those who set up in their tracks. It's good! He compliments your team nicely!
Good luck in the sand!