What about a Special Wall Tank using Assault Vest?
Milotic @ Assault Vest
Trait: Competitive
EVs: 248 HP / 252 SAtk / 8 SDef
Modest Nature
- Hydro Pump / Surf / Scald
- Ice Beam / Blizzard
- Hidden Power [Fire]
- Mirror Coat / Surf / Scald
EVs to give Milotic an odd # of HP for SR, max SAtk, and a little added bulk to go with it's base 125 SDef. Competitive activates and boosts Milotic's SAtk to a very nice 656. First slot comes down to wanting power, accuracy, or chance to status. Ice Beam for coverage, but can run Blizzard if you want to risk it. HP Fire to cover Steel types that wall this set. Last slot you could either go Mirror Coat (which is a Special Attack) to use your bulk against your opponent, or Surf/Scald if you went Hydro Pump with your first slot for an accurate alternative.
Maybe you could slash Dragon Pulse in there somewhere if you wanted a solid base 90 attack, but I feel with Ice Beam/Blizzard being there to stop Dragons, it's kind of pointless.