Was there ever a time tiering leaders said no counters=broken=ban time? If there was I wish those days existed still...
I don't think I'm wrong when I say most people are leaning against a ban, but even if you are I hope you can consider what I have to say with an open mind.
Mew has no counters and extraordinarily few if any checks, period the end. Can we agree on this?
Incidentally 0/0 Meloetta has basically 0 chance to beat NP Dark pulse Mew one on one because +2 LO Dark Pulse does over 60% to +1 Meloetta. They don't check each other at all, if one of them set up a single boost for free the other has no chance to win. This is pretty much a fact.
But certain Mew sets do have counters like how Sableye almost always counters SD or stallbreaker Mew while NP Mew can be always phazed out by um...Slowking. Baton Pass can be foiled by Roar or Dragon tail depending if mew has Taunt or Sub.
The problem I see is one Mew counter can fail spectacularly if it comes in on the wrong mew set. Go back to Sableye for one moment. You assume your opponent was running SD Mew since he had no other form of priority on his team, not a bad assumption at all. And then he uses NP instead of SD.
So now he can use Fire Blast to murder you or Giga Drain to heal and hurt and Dark Pulse will certainly hurt you too. Not only did you lose what could have been an integral member of your team you are facing a +2 mew who probably is still at 50% or so.
That's only part of the reason why Mew is broken.
Another is it's absurd bulk. Let's go back to the NP Mew scenario one more time please. You are saying to yourself, I am sure, "hilarious why are you assuming that we would let Mew set up if we didn't have a reliable answer to him?" And that is a totally legitamate concern, most Pokemon that can ravage teams after a turn of set up often do not have the bulk to do the actual set up - just for instance take Agility PZ who even with significant HP investment is still too frail to reliably set up.
Mew though does not face that problem because of his bulk which allows him to take hits from any defensive Pokemon as well as unboosted moves from relatively powerful attackers. Raikou's Thunderbolt might have KO'd PZ but it certainly won't instantly kill Mew.
So there are times that Mew can set up on almost every team unless you are trying out Mono-dark or some other stupid theme.
And to address the latest arguments to keep Mew in UU we must address this whole idea of diversity, of excitement. Mew makes games exciting so he should be allowed in UU.
I was under the impression that playing excessively conservatively when I see Mew on my opponent's team made me have less daring plays only in order to try and counter the counterless Mew and then make the game less exciting. But that's just me.
Mew has no counters. Mew can easily score surprise cheap KOs if you don't guess the right set. Mew is almost the bulkiest sweeper in all of UU. Mew forces you to play conservatively, or as I put in my Mew 101 post with almost only strong attackers. And you know what basically everything I said is a fact not an opinion.
So please do consider for yourself if mew should remain in the tier.