Some arguments against Do Not Ban.

Team Previews let you see if there's a common Illusion Pokemon on the enemy team. You cannot identify Illusion at Team Preview like you can normally as it's Zoroark's signature ability. Most of these Pokemon like Mega Gengar have quite a few sets and it's impossible to tell without finding out in battle whether the opponent has Illusion or not.

Hazards let you see whether a Pokemon has Illusion or not. This is more difficult if you run Spikes which is in my opinion the superior choice for hazards. This also doesn't prevent someone from leading with an Illusion Pokemon and in my honest opinion someone shouldn't have to feel obliged to run Imposter Chansey to scout for Illusion. Currently with the amount of bugs regarding Illusion (the opponent having 8+ moves after a while, a 7th Pokemon slot appearing, and the incorrect Pokemon being shaded below the avatar once the Pokemon faints), it's difficult and annoying to have to micromanage someone's health. It was better in Gen 6 when a lot of walls ran Status moves like Will-O-Wisp to deal with Shedinja but now it's different and those Status moves aren't as common. I simply don't believe someone should have to micromanage health bars to avoid one of their Pokemon being knocked out due to said bugs.

Running Illusion makes your Pokemon significantly weaker than running other abilities with the same sets. This is false. You can run a Choice item to make up for the lack of power and tricking your opponent into switching out and getting a free hit because of it is often more beneficial than if you ran the same set without Illusion. Not to mention Mega Evolutions and Red Orb Groudon benefit from it immensely. Next to nothing can take a Nature's Madness and Night Shade from Mega Kangaskhan while you never know if it's really Mega Kangaskhan until the moment it Mega Evolves. Red Orb Groudon can Shell Smash and a +2 V-Create basically OHKOes any non-Flash Fire/Unaware wall in the tier except for Zygarde-Complete, which Groudon just runs Ice Beam or Icicle Crash and that's gone anyways. All the while Imposter Chansey can not Transform into them.

I think Illusion isn't as big of a problem as other things right now and banning other things may make Illusion balanced. You should focus on the meta as it currently is, not the future meta.

Illusion is hardly used at all. Usage is never an argument to vote Do Not Ban. This very same conflict came up with the Gothitelle Suspect, which is another reason I mentioned it.

Illusion is only a problem once in battle. I've seen some confusion here. Illusion re-activates if the Illusion Pokemon switches out and switches back in. The problem is that the Illusion Pokemon can then be disguised as a different Pokemon after that. You can disguise as Registeel at first, but later in the battle they could be a Primal Kyogre, for example. Anyways, let me go ahead and refute some common Do Not Ban arguments that I've been seeing.You cannot identify Illusion at Team Preview like you can normally as it's Zoroark's signature ability. Most of these Pokemon like Mega Gengar have quite a few sets and it's impossible to tell without finding out in battle whether the opponent has Illusion or not.This is more difficult if you run Spikes which is in my opinion the superior choice for hazards. This also doesn't prevent someone from leading with an Illusion Pokemon and in my honest opinion someone shouldn't have to feel obliged to run Imposter Chansey to scout for Illusion. Currently with the amount of bugs regarding Illusion (the opponent having 8+ moves after a while, a 7th Pokemon slot appearing, and the incorrect Pokemon being shaded below the avatar once the Pokemon faints), it's difficult and annoying to have to micromanage someone's health. It was better in Gen 6 when a lot of walls ran Status moves like Will-O-Wisp to deal with Shedinja but now it's different and those Status moves aren't as common. I simply don't believe someone should have to micromanage health bars to avoid one of their Pokemon being knocked out due to said bugs.This is false. You can run a Choice item to make up for the lack of power and tricking your opponent into switching out and getting a free hit because of it is often more beneficial than if you ran the same set without Illusion. Not to mention Mega Evolutions and Red Orb Groudon benefit from it immensely. Next to nothing can take a Nature's Madness and Night Shade from Mega Kangaskhan while you never know if it's really Mega Kangaskhan until the moment it Mega Evolves. Red Orb Groudon can Shell Smash and a +2 V-Create basically OHKOes any non-Flash Fire/Unaware wall in the tier except for Zygarde-Complete, which Groudon just runs Ice Beam or Icicle Crash and that's gone anyways. All the while Imposter Chansey can not Transform into them.You should focus on the meta as it currently is, not the future meta.Usage is never an argument to vote Do Not Ban. This very same conflict came up with the Gothitelle Suspect, which is another reason I mentioned it.I've seen some confusion here. Illusion re-activates if the Illusion Pokemon switches out and switches back in. The problem is that the Illusion Pokemon can then be disguised as a different Pokemon after that. You can disguise as Registeel at first, but later in the battle they could be a Primal Kyogre, for example.

I've heard a lot of Do Not Ban arguments here. I'd like to give my side of the argument here. Do I think Illusion is overpowered? No. It's not. It's a weak ability, as it doesn't provide power to any moves like Adaptability, Tinted Lens, or Technician does. It doesn't give you any defensive utility like Fur Coat, Unaware, or Poison Heal does. It doesn't give your teammates any sort of utility either like Weather abilities do. By all accounts, it's not overpowered because it doesn't boost anything.However, we must remember that a Suspect Test does not only aim to see whether something is overpowered, it also seeks the community's opinion and most importantly, whether something is uncompetitive. I am extremely confident that Flint would not have done this Suspect Test if he didn't believe Illusion was uncompetitive.Let's take a quick moment to compare this Suspect Test to the recent Gothitelle and Gothorita Suspect Test that Ubers had. Gothitelle and Gothorita were very weak Pokemon in the tier respectively, however Nayrz suspected them because he believed that they had an unhealthy presence in the tier due to their trapping capabilities. Even though we're talking about Balanced Hackmons, I felt like I should have mentioned this because these are twoscenarios. Gothitelle and Gothorita ultimately didn't get banned disappointingly even though they could trap something passive and set up on it until it struggles or Gothitelle/Gothorita get to max boosts. The reasoning people did not ban it was because they felt it didn't have a big enough presence in the tier and that they were weak Pokemon on their own. I hope that the same scenario does not happen here, as even though Illusion may not be inherently powerful or used often, it's still a problem in that it can eliminate checks to specific Pokemon without any sort of counterplay.That answers that. So why do I think Illusion is banworthy? Well, imagine this. You can control who your Illusion Pokemon is disguised as, right? Well, you can disguise your Pokemon as a Mega Diancie in battle. The opponent will switch out and you have a free turn to doYou can use a Choice Specs Mega Gengar with Moongeist Beam and then the Mega Diancie check will be in a pinch. Let's say it's Registeel. Their Registeel is at low health and if it's not Prankster, the opponent has to choose between sacking their Registeel or switching out again. If they sack their Registeel, then chances are you win solely because you can mow your opponent down with Mega Diancie because they lost their Diancie check. If they switch out, then chances are they're gonna end up taking huge damage on another Pokemon.Let's look at this the other way. You could also disguise yourself as a passive mon like Registeel. The opponent will predict you will U-Turn or the like, and they'll play accordingly. Then you have another advantage because the opponent can't make a counterplay.Illusion is ridiculously effective and is banworthy because of this. You can disguise as a specific Pokemon and then use a highly offensive Pokemon like Mega Gengar to eliminate checks for the Pokemon that you're disguising as. If Mega Gengar is disguised as Mega Diancie and hits the opponent's Registeel with a Specs Moongeist Beam, their Mega Diancie check is in huge danger at that point. This ends up significantly leaning the odds of winning in your favor as if the opponent can't check your Mega Diancie, Mega Mewtwo Y, Mega Rayquaza, or whatever mon, then they will get swept by those mons. Likewise, if an Illusion Pokemon disguised as Registeel knocks out the opponent's Mega Mewtwo X, they're gonna have a more difficult time taking out your Registeel.I hope that anyone who initially wanted to vote Do Not Ban will reconsider based on my arguments.