Firstly, you're all assuming that Ferrothorn can get 4 layers of hazards straight off. That practically never happens unless your opponent just sucks. Seriously, I'd just lead with Fighting Arceus if I had it on my team and I played this team. You wouldn't even know which Arceus the opponent is running either since they don't show you which form in Team Preview. I'd presume you'd just lead with Tyranitar or something. There is absolutely nothing that can threaten it whatsoever. Then, the Fighting Arceus would just Calm Mind up as you go switch to Giratina, then take as you say, about 45% to Ice Beam then phaze it out. If Giratina had Recover or something, I'd say it's a decent answer, but it doesn't have reliable recovery. Fighting Arceus can easily come in again and again (and don't tell me hazards, because you're going to find at least 2-3 free turns before they start getting taxing to Arceus at all. Before that, he would have easily blown massive holes in your team just by Calm Minding up, then firing off attacks. Giratina can't take Fighting Arceus forever either, since with Sleep mechanics and RestTalk, you're easily getting 3HKOed, something which you're not going to be recovering quickly enough from.
So don't call me ignorant ArkhiMarth, I've used Sand teams in Ubers for a very long time, now, probably longer than anyone in 5th gen, and I can tell you that Fighting Arceus is probably one of the biggest threats to Sand teams to exist, and unfortunately, I don't think this team has an adequate enough response to it.
Whatevs sig. QC member for OU and Ubers, VM me for a look at your analysis. Just make sure it's good.
Also, if you want me to rate your team (OU/DW OU/Ubers), give me a VM. If I don't rate it, it's either 1) it's so shit it's too much trouble, 2) I'm busy, or 3) the team is fantastic and I have nothing I can suggest to you. You should be able to recognise which one.