Very little has changed for Milotic defensively since ADV, but that's not always a good thing. Diamond/Pearl has brought with it new monstrously powerful sweepers such as Nasty Plot Infernape, Dragon Dance Outrage Dragonite and other threats that Milotic simply doesn't have the power to stand up against. Worse yet, Hypnosis's accuracy is now a measly 60%, and with Wish becoming more and more useful, Milotic finds itself commonly overshadowed by Vaporeon.
That being said, Milotic finds itself landing very comfortably in its new niche in Generation 4's Underused tier, where it provides an extremely viable choice as a bulky Water-type and status absorber. Its movepool may not be very large, but it's focused perfectly for its job in UU, where it can stand up against strong threats such as Blaziken, Feraligatr, and Azumarill with ease. With its solid 95/79/125 defenses, access to Recover, and ability to hit back with 100 base Special Attack, Milotic is a great choice for any kind of team in UU.
Milotic's excellent 95/79/125 defenses combined with its superb Water typing cement it as an exceptional defensive Water-type. Milotic is capable of sponging hits from many top attackers in UU and either Recovering off the damage or hitting back from 100 base Special Attack. Hidden Power Grass is used to hit threats such as Feraligatr, Azumarill, and other Water-types who Milotic can wall effectively. Recover gives Milotic great utility as a self-healing bulky Water and makes it very difficult to take down.
The last move is an issue of choice. Ice Beam can hit Altaria, Venusaur, and Torterra. However, be wary of faster Venusaur and Torterra variants, as they can easily outspeed Milotic and OHKO with their STAB Grass-type attacks. Haze is incredibly useful to remove stat boosts from opponents such as Feraligatr, Calm Mind Slowbro/Spiritomb, and others. Finally, Toxic is useful for hitting walls such as Slowbro, Tangrowth, and opposing Milotic, who are more than happy to switch into Milotic.Team Options & Additional Comments >>>
Even though Milotic has access to Recover, there are certain advantages to a Sleep Talk set for a Pokémon such as Milotic. The most significant one is Marvel Scale. Milotic's unique ability increases its Defense by 50% whenever it is affected by a status, which means that while Resting, Milotic is extremely difficult to take down. The other is that Milotic often finds itself as the target of status such as Toxic, which it wants to get rid of as quickly as possible. Surf and Ice Beam comprise the standard Water-Ice offensive pairing, giving the best two-move coverage that Milotic can find. Hidden Power Grass also provides useful coverage, allowing Milotic to hit opposing Water-types such as Feraligatr and Slowbro, but renders you unable to hit Altaria or Grass-types.
The EVs give maximum physical bulk, while still preventing Moltres from 3HKOing Milotic with Hidden Power Grass. This also makes Milotic an extremely effective mixed wall with the Defense boost from Marvel Scale, achieving 394 HP / 366 Defense / 330 Special Defense while sleeping.Team Options & Additional Comments >>>
This set is focused to make great use of Milotic's special bulk, giving it the role of Toxic staller or Hazer. Surf gives Milotic a reliable STAB move and allows Milotic to do a significant amount of damage to those that don't resist it, thanks to Milotic's decent Special Attack stat. Toxic allows Milotic to inflict status on fellow bulky Water-types who might otherwise be troublesome for the team and forces offensive teams to keep switching out, thereby racking up passive damage. In the third slot, any of the three listed moves are effective depending on Milotic's teammates. For example, a team lacking a hazer/phazer and no reliable way to get rid of bulky set-up sweepers will certainly benefit from Haze on Milotic. Ice Beam can prove useful if your team has problems with Grass-types such as Venusaur and Sceptile; with the correct prediction Milotic can inflict great damage to the opponent's Grass-type pokemon. Ice Beam can also be used to pick off weakened sweepers that are immune to or resist Surf, such as Toxicroak and Ludicolo. Hidden Power Grass can be used if you like to get rid of annoying entry hazard setup Pokemon such as the Rock/Water type brothers, Omastar and Kabutops, though it is worth noting that this move will be more effective on a more offensive Milotic spread.Team Options & Additional Comments >>>
Milotic's base 100 Special Attack and base 81 Speed make it a perfectly viable offensive Pokémon. With Choice Specs, Milotic makes an exceptionally bulky Choice user, backed by a STAB Hydro Pump, one of the strongest attacks with one of the best offensive typings in the game. Surf is more reliable, having perfect accuracy but significantly less power. Ice Beam is the staple coverage move for Water-type Pokémon, providing coverage against Grass-types and Altaria. Hidden Power Grass hits Water-types attempting to wall the first two moves and works especially well against Gastrodon and Quagsire. The final move is up to personal preference. Hypnosis can take one of Milotic's counters out of the game relatively early, but its shaky accuracy often makes it little more than a gamble. Surf may seem redundant, but given that Milotic is short on offensive options, having the option of attacking with either Hydro Pump or Surf on the same set can come in handy. Speed is maximized in order to outspeed all base 80 Pokémon, such as Blaziken and Altaria, as well as all neutral variants of base 90 Pokémon such as Moltres and Porygon-Z.
Item choice is a matter of preference. Choice Specs provide the maximum amount of power to punch through teams. Choice Scarf gives a solid method of revenge killing many scarfed or speed boosted threats, such as +1 Dragon Dance Altaria or Scarfed Medicham. Finally, Life Orb trades bulk for versatility. If Life Orb is used, Recover is an option in the last slot, as Milotic can use the ability to recover the HP sheared off by Life Orb.Team Options & Additional Comments >>>
With sturdy defenses, excellent type coverage, instant recovery, and a solid 100 Base Special Attack, Milotic has all the tools to be a premier tank in UU. Hydro Pump is the main attack and absolutely tears through most of UU. Ice Beam is for coverage and will make Venusaur think twice about switching in freely.
The final attack is a general coverage attack to battle with opposing Water-types. Hidden Power Grass gives you a solid way to deal with Stockpile Gastrodon and can at least dent Lanturn, but Hidden Power Electric has better neutrality as a whole, which can make it more difficult for opponents to switch in. Recover allows Milotic to switch in multiple times throughout the course of the battle and replenish any health lost from Life Orb recoil.
Most of Milotic's effective movepool is covered in the above sets, but there are a couple of novelty options. Dragon Pulse provides perfect neutral coverage in tandem with Surf, but its lack of super effective coverage makes it a poor choice in most situations. Light Screen can be used to support the team and improve Milotic's ability to take special hits. Meanwhile, Mirror Coat can allow you to surprise opponents who try to hit you with neutral Special attacks that won't KO. Hypnosis used to be a staple on Milotic, but between its now 60% accuracy and Milotic's need for another move in its last slot, Milotic has issues putting it into a set. Flame Orb is marginally viable as an item for Milotic, as it provides a 50% increase in Defense and an immunity to status, but the loss of effectively 18% HP per turn (Leftovers recovery + burn damage) makes it a significantly worse item choice.
It is possible to run Milotic with an entirely Special Defensive set packing 252 Special Defense EVs and a Calm nature to fully utilize its 125 Special Defense, but weaknesses to common special attacking types such as Grass and Electric make it a less appealing option. 8 Speed EVs may seem random, but with those EVs, Milotic reaches 200 Speed, enough to outpace Adamant Max Speed Aggron.
Checks and Counters
Grass-types such as Venusaur and Ludicolo can make Milotic's life hard, as they can hit Milotic hard on its Grass weakness with their STABs while taking low damage from Milotic's offensive options. However, beyond Grass-types, the choice of a Milotic counter is largely dependent on which variant of Milotic you're fighting. Variants without Rest are crippled by Toxic, which continually chips away at Milotic's HP, preventing it from staying in against threats for extended periods of time. Variants without Haze or Hidden Power Grass are pure setup fodder for SubDD or SubSD Feraligatr, who can set up an unbreakable substitute in Milotic's face. SubPunch Azumarill can also provide to be the bane of Milotic without a neutral attack, as they can proceed to Substitute for free before assaulting Milotic with powerful Focus Punches. Toxicroak's Dry Skin ability also allows it to easily switch into Milotic and set up on it, as a neutral Ice Beam is the best that Milotic can muster in return.
Milotic's offensive sets can be beaten with a little prediction. The safest way to switch into offensive Milotic is by using a Water-type such as one's own Milotic or a Slowbro. Altaria also makes a good choice for switching into Milotic, as long as it stays away from Ice Beams. However, the bar none best way to switch into offensive Milotic is using Chansey, who can proceed to either stall it out with Softboiled/Wish or cripple it with Toxic or Thunder Wave.