All in all Arcanine is the best thing on the Slate right now. The others just seem so subpar :/
I can see Mega Latios being a great Spinblocker, but Analytic? You're mostly gonna wanna be fast with Latios (since 110 is 110) so to get that boost you'll need to run Quiet and 0 IVs which is still averagely fast for Latios. Then the opportunity cost of not using Latios, and blah, blah. Not really worth it imo.
Cool core!
Analytic activates for switch-ins, so the boost comes into play more making it more difficult to switch into. You have to remember that there aren't many spinblockers in the tier (Gengar, basically) and Lati would be able to easily block defensive Starmie, while also being able to take 1 hit from Excadrill and knock it out with Surf.
Reliable recovery is another bonus of using it over Gengar.
This could make it a cool addition to the tier.
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As an aside, I think (especially based upon the early reaction to this slate) that we're forgetting about what the purpose of this project is. We're not aiming to always create S+ rank behemoths that wreck the tier, but aiming to improve the viability of overlooked mons, giving them a niche and making them viable for use in the OU tier. Something to bear in mind before shooting down somebody's submission without much of a thought!
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Onto the rest of the slate!
Dragon Dance Luxray: This is a cool addition that gives Luxray a niche in the tier (DDancer that doesn't give a toss about status), but wouldn't make it to the top level - which is fine by me, to be honest!
I think that comparing it to Mega Char X and MAlt is a little harsh, as they occupy the Mega Slot and you can expect more from it. Electric is also a pretty unique typing for a DDancer, with few weaknesses.
Zygarde is a reasonable comparison, but I feel that both abilities were overlooked - Luxray either has an easier time setting up on physical threats, or just hits a lot harder and doesn't care about status. Electric+Normal (facade pseudo STAB) gives pretty impressive neutral coverage, especially when backed up by Superpower to remove Ferrothorn. Maybe the slate could be adjusted to give it Bolt Strike/Fusion Bolt? It would take away the recoil issue.
The not caring about T-Wave is a big thing now as well with it being particularly popular to spread yellow magic at the moment (Clef, Klef, Thundurus, Ferro, Starmie (yuk), and others).
It's main problem is not outspeeding Lopunny+Mega Man at +1 to be honest, and it really needs to run Jolly.
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Electric / Dark Thundurus-T: I really like this. As
Valmanway mentions, the STAB coverage is pretty spot on, and this opens up lots of possibilities for the Double Dance set, as well as for the Scarf Set. Modest Thundy-T hits like an absolute truck, and not being weak to SR means it could come in more often. Also that Dark Pulse flinch chance :)
Something else worth mentioning is that Thundurus-T has the movepool and stats to pull of a niche Physical lure set, boasting STAB Knock Off, Superpower, + Wild Charge off a reasonable base 105 Attack
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Fire / Normal Arcanine + Swords Dance: Soooooo much love for this :) Bring back Scarf Lando-T meta I say!
+1 252+ Atk Life Orb Arcanine Extreme Speed vs. 0 HP / 24 Def Landorus-T: 265-312 (83 - 97.8%) -- guaranteed 2HKO hoooooooly shiiiiiiiiii......
Maybe Lando-T might not make its come back after all!
The normal typing gives it an extra immunity while burdening it with a fighting weakness, not a bad trade to be honest.
I was just doing some calcs thinking that the same things that check Lucario would check Arcanine, but no.. the STAB Espeed makes a massive difference, OHKO'ing the Lati's and Lando-T. What this might do is bring Terrakion back into contention to check it, or even see Cobalion rise in usage:
112 Atk Cobalion Close Combat vs. 0 HP / 4 Def Arcanine: 320-378 (99.6 - 117.7%) -- 93.8% chance to OHKO
It'll be difficult to counter depending on its coverage move (Wild Charge/Close Combat), but easy enough to revenge kill (especially with the popularity of Scarf Tar right now).
+2 252+ Atk Life Orb Arcanine Wild Charge vs. 252 HP / 252+ Def Mega Slowbro: 234-278 (59.3 - 70.5%) -- guaranteed 2HKO I guess Bro counters it with ease...
It would also be the only 'mon in OU that resists Fairy/Ghost and Dragon/Ghost :)