[Guide] Top Metagame Threats

[Dragonstrike]

Actually, Moody was banned because it was uncompetitive, not because it was overpowered or because there existed more than one Pokemon with it.

One of Smogon's frameworks for tiering is to make the metagame as competitive as feasibly possible, which essentially boils down to facilitating an environment in which a worse player does not have access to strategies which allow them to beat a better player through luck. This is why Double Team and Minimize are banned.

Moody is uncompetitive because it is incredibly luck-based. Using Moody requires almost no skill and amounts to hoping you get Evasion boosts in order to eventually luck your way to victory. This aspect of the game was deemed uncompetitive and counterproductive to a healthy metagame by Smogon, which is why it was banned.

Fair enough, but my reasoning still stands as well.  The uncompetitive aspect isn't just in the short term luck, but also that short term luck's long term effects.  And when you can stall to increase the odds of that luck actually occurring in that short period of time, that's when it becomes really unfair.

Nobody likes those completely luck based strategies, it's true, but it gets worse when those strategies become less reliant on luck.  Just look at the Endless Battle clause.  Totally not a luck based strategy, but still banned all the same (even in Anything Goes iirc).  Moody can get to the point that Double Team and Minimize reach given enough time, and it will have accumulated tons of other boosts while doing so as well.  Luck based?  A little.  But not as much as pure evasion or SwagPlay, for example, as those stat boosts everywhere can go a loooonnnng ways.

[Morshu]

If I recall correctly, I heard someone from Smogon mentioning that Moody might even have not got the ban if it didn't raise evasion. It's true that with a lot of boosts, the Pokémon can become overpowered, but if you look at the strongest Pokémon that actually get the ability (Bibarel, Glalie, Octillery, Smeargle). They can use Protect once, maybe twice, to get free stats boosts, but once that is over, they're very weak to a counterattack simply because their stats are so low. The possible evasion boosts are the only reason the Pokémon with Moody can actually take blows, and that's by not taking blows at all.

[Lord Windos]

I don't quite get why Evasion is such a bad thing in the Pokemon competitive scene. Isn't dodging damage better than taking less of a hit? Can someone explain why evasion moves/abilities are banned so often?

[Iron]

Because then your win or loss comes down to a coinflip rather than to strategy.

Defense Curl reduces damage by a predictable, consistent amount. But with Double Team, you could run the same battle twice and get very very different results.

[Dragonstrike]

What Iron said. Coin Flips aren't as fun. You can sort of argue the same for accuracy loss, but there's one difference between Evasion boosts and Accuracy debuffs: it's extremely hard to switch out an opponent spamming evasion boosts. With accuracy loss, you can just switch to another pokemon to eliminate the effects entirely. With Evasion boosts, you can guarantee your opponent is NOT switching out because they're abusing a stat boost, and you can't force them out either with a phasing move. With enough boosts, the chance to dodge is also betetr than a coin flip, which is a terrible combination for a fun competitive environment.

[PhantomUnderYourDesk]

Asking in friendly and curious way since my practical experience in competitive metagame dwells somewhere between 0 and 1, but goes the banhammer on Snow Cloak and Sand Veil as well?

Saying, my Glaceon holding an Icy Rock forces a hail with the same-called move, which boosts its evasion thanks to the ability Snow Cloak. Using the move Barrier it beginns raising its Defense while giving constant damage to the opponent if they aren't protected from the weather condition, then sweeping with Blizzard, which has a accuracy of 100% during hail. How big is the luck-based aspect in that case?

[Dragonstrike]

Asking in friendly and curious way since my practical experience in competitive metagame dwells somewhere between 0 and 1, but goes the banhammer on Snow Cloak and Sand Veil as well?

Saying, my Glaceon holding an Icy Rock forces a hail with the same-called move, which boosts its evasion thanks to the ability Snow Cloak. Using the move Barrier it beginns raising its Defense while giving constant damage to the opponent if they aren't protected from the weather condition, then sweeping with Blizzard, which has a accuracy of 100% during hail. How big is the luck-based aspect in that case?

Snow Cloak and Sand Veil give a 20% evasion boost, and it stacks with other evasion sources (such as stat buffs [chance to dodge increases a lot as the stat boosts accumulate] or items like bright powder [a 10% evasion boost]) if used like that.  It's not as broken as when weather wars were a thing in gen 5 of the series, but it's still fairly significant due to that stacking.

Evasion ability plus evasion stacking plus decent bulk = the ban hammer from Smogon.  Don't ban evasion in general, and you'll see sets like that often, dragging out battles in a luck based evasion war.  Heck, even Bright Powder by itself is banned, because it's a luck based complete negation of damage.

[PhantomUnderYourDesk]

Thank you the answer.

(...)
Evasion ability plus evasion stacking plus decent bulk = the ban hammer from Smogon.  Don't ban evasion in general, and you'll see sets like that often, dragging out battles in a luck based evasion war.  Heck, even Bright Powder by itself is banned, because it's a luck based complete negation of damage.

Oh well... at least it isn't banned in-game. 'Cause in the Battle Subway (Gen.5) I've been actually quite sucessful with that set on a timid Glaceon - well, at least if it wasn't OHKOed by a nasty super-effective attack in the first place. ┐(´~｀)┌

[Dragonstrike]

Thank you the answer.

(...)
Evasion ability plus evasion stacking plus decent bulk = the ban hammer from Smogon.  Don't ban evasion in general, and you'll see sets like that often, dragging out battles in a luck based evasion war.  Heck, even Bright Powder by itself is banned, because it's a luck based complete negation of damage.

Oh well... at least it isn't banned in-game. 'Cause in the Battle Subway (Gen.5) I've been actually quite sucessful with that set on a timid Glaceon - well, at least if it wasn't OHKOed by a nasty super-effective attack in the first place.  ┐(´~｀)┌

Evasion isn't even the best way to trash the Subway.  If you want to completely trash it, use a rain team.  Destroys every single mode (assuming you have a non-AI partner for multis, of course).  Muddy Water in the rain OP, btw 

[PhantomUnderYourDesk]

Oh, thanks for the hint, @Dragonstrike... It's more than gladly taken in consideration. The Multi is indeed the only one I'd didn't manage to complete yet. Well, I need to convince my default ever-lazy not-AI battle partner to give it a few more tries... ._.