Hey B3N, I was going to rate this but I haven't really got around to it until now. Looks solid, I've always like rain in NU :] my suggestions aren't vital but they should help the team perform better as a whole.
I see what you're trying to do with him, but you gotta remember that he's famous for that set in NU so most opponents won't be setting up hazards on him, they'll be straight up attacking. And by tricking them a band you've basically just guaranteed your death :p I'd go with the standard set, with sitrus berry over choice band, and shadow claw over switcheroo. You'll also want a jolly nature, as crazy as it sounds, you have enough attack already and you need to outspeed timid haunter. Put the other 4 EVs in HP.
Thunder > reflect to abuse the rain, and heal bell > thunder wave as a lot of your sweepers are crippled by burn & paralysis.
252 HP / 252 Def / 4 SDef is better as it backs up your Ampharos's ability to take most special hits. Also, Dive seems like a good stalling idea on paper, but what it really does is make you setup bait to anything with substitute; use waterfall.
I like this guy, he can make short work of Amoonguss clearing the way for a Wailord sweep. Take off rain dance for aqua jet which is boosted by the rain and can finish off weakened opponents. Lastly, put 4 EVs in defense and give him a jolly nature to outspeed scarf braviary, gardevoir etc. under rain. IMO superpower > brick break, you're boosting your attack anyway and the extra power is helpful for smashing regirock & friends.
Your current set isn't contributing much to the win condition of your team, you're also lacking stealth rock so it would be helpful on this guy.
Golurk @ Expert Belt
Trait: No Guard
EVs: 92 HP / 252 Atk / 164 Spd