Pokémon More Sun / Moon and Zygarde updates!

How strong Z-Move Eevee I think entirely depends on whether Z-Moves get priority like Mega Evolving, and whether it is allowed to Baton Pass those boosts.

At the moment Smogon's Ubers/1U doesn't have any restriction on passing those boosts, so either it'd be a pure gimmick strategy if it has no priority as it would depend on Thunder Wave or Tail Wind to be able to setup against offense teams, but if it does have priority then if Eevee can be EV'd to survive well enough while retaining enough speed to pass before taking a second hit, it could be a legitimate threat.

Where it can't Baton Pass, it's still scary for sure. STAB Adaptability Hyper Voice + 220 BP Stored Power + Shadow Ball + Hidden Power off of 414 SpA + Heal Bell to get rid of status is no joke. But with or without priority uber +2 to everthing boosts, Eevee mostly relies on its absurdly boosted Normal/Psychic attacks for offensive power, which makes anything that resists that combo a potential threat to Eevee especially if they carry phazing. Tyranitar, Ghost/Darks and bulky Steel-types (SpD Registeel is especially good at shutting Eevee down) are among those that can counter Eevee. Someone on the Smogon thread predicted something like RU for Z-Move Eevee, and I think that'd be a fair assessment.

Edit: And of course, with or without priority I don't see any chance that Eevee's Z item wouldn't be quick banned from LC.

 

Some very interesting new things:

Spoiler: Z Move Celebrate, Happy Hour, Hold Hands, Conversion and Geomancy (+1 All Stats)

The've become a status move that gives +1 to all stats. A bunch of meaningless event moves suddenly becomes super boosting moves. Even if Evoboost Eevee isn't a problem, now you'll have +1 to all stat Eeveelutions with access to Baton Pass too.

Pokemon with these moves:
Bulbasaur, Ivysaur, Venusaur (Celebrate)
Charmander, Charmeleon (Celebrate)
Charizard (Celebrate, Hold Hands)
Delibird (Happy Hour)
Eevee (Celebrate, outclassed by Evoboost)
Eeveelutions (Celebrate)
Greninja (Happy Hour)
Ho-Oh (Celebrate)
Inkay, Malamar (Happy Hour)
Jirachi (Happy Hour)
Magikarp, Gyarados (Celebrate, Happy Hour)
Meowth (Happy Hour)
Pikachu, Raichu (Celebrate, Happy Hour, Hold Hands)
Porygon, Porgon2, Porygon-Z (Conversion)
Rayquaza (Celebrate)
Smeargle (Any)
Vivillon (Hold Hands)
Xerneas (Geomancy)

Spoiler: Z Move Splash (+3 Attack)

Raises Attack by 3 stages. ALL HAIL MAGIKARP

Pokemon with these moves:
Azurill, Marill, Azumarill (Has Belly Drum)
Buneary, Lopunny
Clauncher, Clawitzer
Cleffa, Clefairy, Clefable (Has Belly Drum)
Delibird
Feebas, Milotic
Finneon, Lumineon
Hoppip, Skiploom, Jumpluff
Horsea, Seadra, Kingdra
Luvdisc
Magikarp, Gyarados
Mantyke, Mantine
Poliwag, Poliwhirl, Poliwrath, Politoed (Has Belly Drum)
Spoink, Grumpig
Wailmer, Wailord
Wynaut, Wobbufet

1U/Ubers gets a couple new toys with Z-Boost All Stat Rayquaza, Sylveon and Ho-Oh. Mons with Dragon Dance/Quiver Dance/Geomancy probably won't really use Z-Boost All moves unless they also really enjoy the defense boosts. Wherever SpeedPass isn't banned will also have to beware of ALL Eeveelutions passing +All Stat boosts and not just Eevee. Stored Power is an egg move for Eevee, so (un)fortunately Espeon can't abuse Z-Celebrate (Event move) + Stored Power.

Non-mega Lopunny actually becomes dangerous getting a half-Belly Drum boost thanks to splash, and it can also Baton Pass that boost to something else. +3 Gyarados in 1 turn is pretty nasty too, especially if it can get a Salac boost or something. Azumarill could use it as a half-Drum boost that doesn't damage itself, but apparently Z-Belly Drum recovers before cutting HP so Z-Splash might be outclassed on those mons.

Alola Ninetales has Snow Warning as its Hidden Ability, has STAB Blizzard and Moonblast, gets Aurora Veil (instant dual screens, heard it only works in hail but Snow Warning brings hail anyway), and 9 Attack moved to Speed (109 Speed total), and according to the data mine I read, it still gets Heat Wave as an egg move. Definitely going to be a VERY strong Pokemon.

Additionally, Torkoal gets Drought, Vanilluxe gets Snow Warning, Gigalith gets Sand Stream and Pelipper gets Drizzle, so we're getting plenty of new weather setters.

Silvally has 95 in all stats. It's kinda different from Arceus, it can change its typing with 'Memories' the same way, but it lacks much of the defensive utility Arceus formes have. No Recover, no Defog. Instead, it gets some great offense moves including Parting Shot, U-Turn, Pursuit and Explosion. Looks like it'll be fun to play with.

Lots and lots of more things to go over, but so far Sun and Moon looks to be quite fun. Can't wait to see how it turns out.

 

Update on how Z-Status moves work, they first apply the Z effect, then the original move is used. So for example, Z-Lovely Kiss first applies +1 Speed then uses Lovely Kiss like normal. List of Z-Status Moves here: Status Z-Move Bonus Side Effects - Pastebin.com

Some of the more interesting things:

Z-Trick/Switcheroo gives +2 speed before swapping items. So assuming the Z-Crystal gets consumed, it's like a sort of Thief/Agility combo.

Z-Stockpile gives full recovery and applies +1/+1 defense. Unfortunately only works one time, but tanks like Snorlax and Guzzlord could use this to not only instantly recover HP, but also make them even harder to wear down.

Z-Parting Shot recovers all HP to the Pokemon that switches in. I wouldn't be surprised if Alola Persian ended up OU (Smogon) just because of its use on VoltTurn teams. Seriously, a fast Pokemon that simultaneously switches out, restores a Pokemon to full HP and reduces the target's offenses is crazy. Its offenses are crap, but it still has regular Parting Shot after the Z-Parting Shot, Fur Coat, Nasty Plot with decent Special coverage, 115 Speed, STAB Foul Play, Hypnosis and Taunt to work with. I'm actually thinking it could even be a viable niche pick in 1U.

Z-Memento also recovers all HP, but still unfortunately KOs the user. Still a combined Memento+Healing Wish though, so fast Pokemon could make use of it.

Z-Psych Up gives 100% recovery in addition to copying stat boosts. Regigigas now has real recovery.

Z-Mirror Move gives +2 attack. Could help some birds like Pidgeot in lower tiers, and has some situational use afterwards too.

Z-Conversion both raises all stats by 1 and changes the user's type to its first move. Porygon-Z can simultaneously get 50% boost to all stats while changing its type to Ghost, Dark, Ice, Electric, Psychic or Bug and gaining Adaptability STAB for the type of your choice.