Great team, but I'm having trouble understanding the use of Choice scarf on Venusaur with the move sleep powder. It is always great to put something to sleep before it can make its move, but due to your scarf, you are also obligated to switch out.
The advantage of a Scarfed Sleep Powder is that it essentially removes the opponent's lead from the game right away. Sure, you need to switch afterwards, but the opponent is down a pokemon, which is a great tradeoff.
@Soto: Awesome team. My biggest concern is that your team is very weak to Nasty Plot Mismagius. Even Registeel and Milotic don't fare to well, as many carry HP Fighting for 'Steel, and almost all have Thunderbolt, which OHKOs Milotic and does a chunk of damage to Registeel. Absol can take out non-Substitute versions with its priority Sucker Punch, but fears HP Fighting. An unorthodox counter would be Tauros.
Tauros@ Life Orb/Choice Band
Jolly, 4 Def, 252 Att, 252 Spe
Return
Payback/ Pursuit
Stone Edge
Earthquake
Tauros is immune to Shadow Ball, and can outspeed OHKO Mismagius with Pursuit or Payback. With Intimidate, he also has surprising physical bulk, all while being among the most underestimated pokemon in UU/NU. Just be sure to use a Jolly nature and max speed to guarantee you're faster. I'd put him over Arcanine or Hariyama (Probably Hariyama. Milotic can absorb status thanks to Marvel Scale, and Tauros has the same coverage)
Just some nit-picking stuff now. Milotic probably wants Ice Beam over HP Grass. Rotom handles bulky waters for you, and Ice has overall more useful coverage.
Use Iron Head on Registeel, especially if you opt for Tauros. Shadow Claw may hit Psychics and Ghosts harder, but you'll notice the power loss evereywhere else. Iron Head's flinch rate works well with Thunder Wave too, giving you a paraflinch combination.
Besides that, great job, and good luck!