I have been playing this format for a much shorter period of time than most of the others who have already commented on this thread, but from my time I found that Gengar is a problem. I understand why people would not think its ban is needed as it helps stabilize some teams from just straight losing to tapus and other fairies, allows a lot of pokemon that normally wouldn't be seen in the spotlight to shine (for example kommo-o), and in general is a lot more splashable on teams at this time due to its diverse move pool and ability to limit your opponent while benefiting you. However, with this being said these reasons have been proven to be very overwhelming in the current meta to the point where a good portion of teams you will see have Gengar because its the best way to play at this time.



There are some counter strategies out there such as running Manectric which may as well be the second most common mega due to being faster than Gengar and being able to snarl and pivot around, but that's about all the diversity you'll see. Gengar has such a stronghold on this metagame that it almost gets boring to watch and play since the outcome is typically very similar. Gengar is so important in match ups that you even see big games come down to "who will win the shadow ball speed tie" as that will decide who can trap and set up better than their opponent in the end. On top of this people are learning new strategies with their trap such as the newly influential sticky web araquanid teams that are running around allowing you to trap -1 speed pokemon making set up much easier.



Speaking of set up, I believe the number one reason this vote is going down is due to the newest version of Gengar set up which has zygarde on it. With Incineroar getting intimidate, it only buffed Gengar even more giving you an intimidating Fire/Dark type to deal with the Steels, Psychics, and other Ghosts that would give it issues otherwise. This gave an open slot to the ground type of Landorus-T, allowing teams to fully abuse the powerful core of Gengar, Incineroar, and Zygarde with the support of tapus such as Bulu or Fini and other key players.



I know I am discussing different team types instead of Gengar itself, but that is because I wanted to describe just what exactly it does. Gengar has so many options it can pull off on so many different team styles. You could splash it on a rain team to basically remove any counter weather play. You can put it on a team with Bulu to counter other Tapus and splash Dazzling Gleam for Kommo-o on it. You can taunt trap supporting role pokemon making them feel almost useless, or you can abuse trapping pokemon that can't touch it and set up a Substitute to allow it's stay power to last even longer. That's not even going over the other ideas like encore, disable, trickroom, and so on that it can throw out there.



I guess what I'm trying to get at is that Gengar is such a diverse move pool that you almost never know what to expect. It's speed stat is insane and it's special attack only compliments it more. Its bulk is good enough to where you can easily support it to make it last even longer, and with the ability to trap it's not like your intimidates are going to waste. Speaking of trap, its ability to trap denies most forms of counter play unless you make some heavy reads and switch before it can get in which is not even a safe bet, or if you run pivoting options on most of your pokemon. This one pokemon has taken over the metagame forcing specific archtypes to be played if you want a shot in higher stakes games, and in general has forced player to run specific pivot moves to even have a chance.



Finally before I end this post I would like to discuss what could happen with it gone. I could see a main concern being that pokemon like Metagross would take over the metagame just like Gengar did, or that fairies would take over due to their biggest threat being eliminated. It's hard to read just where the meta will go, but I feel these fears can be broken down and taken care of a lot easier than just relying on one pokemon to take care of all the issues. With incineroar getting intimidate now, it makes mega evolving with Metagross riskier as well as forces it to have an attack to hit it or else incineroar will always take care of it 1v1. There are also other perfectly good answers to Metagross such as Aegislash, Celesteela, Genesect, and so on that can be used as a method of handling it. As for the fairy issue, I just see this as an excuse since we have so many viable poison, steel, and even fire types that can help deal if the team is built right. Even the feared next big mega, Metagross, would help deal with them easily. Its just the reason we typically never see these answers on teams is because Gengar does the job better than them all and can easily beat most of them too with its powerful stats.



tl;dr:

Gengar runs the metagame with its diverse movepool, great stats, strong synergy with support and set up pokemon, and most importantly its ability. It's stronghold on the metagame is so bad that you'll most likely see a Gengar on a team in a big tournament match just because its basically hurting you not to run it, which leads to most games coming down to who wins the speed tie. Gengar limits a player's ability to outplay their opponent and can end games if it gets the trap right on one turn. Yes it allows for certain pokemon that couldn't normally to shine, but that shouldn't be a reason to keep such an overpowered pokemon in a metagame that is very unhealthy because of it.



If you have any feedback you want to give me or a discussion you want start up with me, feel free to reply and I'll definitely respond. I want to see opinions of others since in the end you guys know more than me and could very easily sway my conclusion in the vote.