Sweeper Mew is arguably more powerful than Tail Glow Manaphy. With Nasty Plot and the Movepool that Manaphy can only wish for (Bolt/Beam, Ghost/Fighting, Mixed Ice / Ground with IceBeam / Earthquake , Dragon / Fire...) there is no single reliable counter to Mew. And that only covers 3 attacks. Throw in a 3rd and you've easily got complete type coverage, or you can taunt to screw walls over, or you can baton pass when the times get tough.
Don't forget, Mew is up there as far as bulk is concerned. Mew can take an Life Orb Weavile Night Slash with no EV investment and KO back with Aura Sphere. With just 28 Defense EVs, Mew will always survive an Adamant Tyranitar Crunch, and will always survive CB Pursuit if it doesn't switch out. Granted, Manaphy reaches a similar level of bulkiness with an arguably better typing and ability for stalling... but thats why Manaphy is banned to Uber as well.
Even if we ignore Baton Pass here... what Mew got over Gengar is major bulk. Gengar cannot survive against LO Weavile Night Slashes, Adamant T-Tar Crunches, or CB Pursuits.
Don't forget, Mew is up there as far as bulk is concerned. Mew can take an Life Orb Weavile Night Slash with no EV investment and KO back with Aura Sphere. With just 28 Defense EVs, Mew will always survive an Adamant Tyranitar Crunch, and will always survive CB Pursuit if it doesn't switch out. Granted, Manaphy reaches a similar level of bulkiness with an arguably better typing and ability for stalling... but thats why Manaphy is banned to Uber as well.
Even if we ignore Baton Pass here... what Mew got over Gengar is major bulk. Gengar cannot survive against LO Weavile Night Slashes, Adamant T-Tar Crunches, or CB Pursuits.




















