As I said, I utilise a niche strategy to beat it, running Skill Swap over Seismic Toss on my Chansey. Yes, it is less effective against 95% of the meta, but I HAVE to run it, because otherwise I will lose a lot. Let me be a bit more in-depth. My most recent team consists of Mew/Dusclops/Nattorei/Chansey/Gyarados/Forretress. Mew is a Spdef Phazer and sets up rocks. It also has Superpower to deter Tyranitar. Dusclops is a Restalk spinblocker with W-o-W. Nattorei and Forry together set up and spin hazards. Natt also helps to deal with rain, and acts as a rock resist. Chansey and Gyarados together deal with Special and Physical threats. Thanks to intimidate, I have considerably less difficulty beating such beasts as Terakion, Dory and DD Kingdra. Gyarados is the second bulkiest intimidator with Rest, Sleep Talk and Roar, and lacks the ugly weaknesses of Mence, specifically to Dragon. Chansey is stupidly bulky, and also cures status. Of that team, the only way I can fit a dedicated Rankurusu 'counter' in is to consolidate Forry and Natt into one Pokemon, Forry. This means I need a way to help deal with rain, resist rock and beat Rankurusu 1-on-1 every time. Maybe I'm missing something, but I don't see a way I can fit a dedicated Rank counter without crippliung the whole team against a lare number of threats. I can get away without a rock resist by swapping Mew for Hippo, but then I'm forced into a corner by random special threats because I can't reliably Phaze them. This is not a crap team. Played well, it beats almost all of top threats out there. But it does not beat Rankurusu without Skill Swap Chansey, a frankly ridiculous measure. You cannot compare Rank with Clefable, because without Magic Guard, Rank would be very good and Clefable would be horrendous. Clefable is beaten by lots of common things. Rankurusu is not. Also, if fable has sub, it only has one attack, which means it will invariably be walled by half the metagame. Or it does not have Softboiled, which means it will be killed by multiple strong attacks.
Somebody name a Rankurusu counter that isn't shit and I'll shut up, provided it works. Until then, it is broken, not because of no good counters, but because of no good counters and the fact it cannot be effectively played around. I'm not refusing to use something from the very small list of things that beat it because they don't fit, or because they open the team up to other threats, I'm refusing because all of them are crap. With the new Pokemon, yes, you can't counter everything. But you can have a team that can deal with everything. Maybe you have to play around certain threats, but that's OK. The issue is that Rank necessitates otherwise almost useless options which a team cannot afford to use in the current metagame.
EDIT: Also, if a Pokemon 100% beats Stall on it's own, it should already have been banned. A single Pokemon beating an entire playstyle is ustterly ridiculous. I have at least three stall players I know who forfeit when they see Rank in team preview because matches against it ARE NOT FUN.