Sorry for bringing up an old thread, but I liked Milotic in ADV and I'm hoping I can find a way to get him to work here.
Speed is important here. If you give Milotic 96 Speed EVs, it outspeeds Adament 252 Speed EV Tyranitar. With max HP and 76 Defense EVs, Milotic is guaranteed to survive Stone Edge and the Sand Stream that follows. Although hopefully you predict correctly and take one of his other, less damaging moves. At that point, Milotic can put Tyranitar to sleep and can recover off the damage. Not anywhere close to a perfect solution, but Milotic switches in, survives, and forces Tyranitar to switch out.
If you put your remaining 84 EVs in Special Defense and use a Calm Nature, you're guarenteed to survive 2 Draco Meteors from Salamence if Leftovers are active. Otherwise, it's about a 50/50 chance. With leftovers working, you can still switch into a Draco Meteor and scare Salamence off.
Milotic @ Leftovers
Trait: Calm
EVs: 252 HP / 76 Def / 96 Spd / 84 Sdef
Surf/HP Electric
Ice Beam
Hypnosis
Recover
The sleep talk set won't work. You're just asking for something to come in and set up on you.
Milotic performs well enough in ideal conditions, but once you add in the minor damage from things like Spikes and Sand Storm, I just don't think that it can keep up in this generation. I'm definately going to try it out, but I don't have high expectations.