Agreeing that Snorlax should be S-rank. I know that his typing isn't doing him any favors, but 160/110 Special Defense is ridiculous, and thick Fat basically grants him resistances to Fire and Ice. Even without a cool set of resistances, Snorlax still walls some of the best special attackers in the game, like Raikou, Zapdos, Chandelure, and Yanmega. Whirlwind is great for racking up hazard damage, but everybody already knows that Snorlax does this well. Doron claims that Snorlax is a setup fodder if it uses Rest, but it's a setup fodder for them even without rest, because Body Slam when not invested into heavily won't hit a physically defensive Pokemon terribly hard.
And as cim already touched on, why does everybody overlook its stellar base 110 Attack? Slap a CB on Snorlax, and all of a sudden it can break through some very physicaly defensive Pokemon, like Bronzong, Registeel, Cofagrigus, and Cobalion as it switches in. It also becomes a very effective pursuiter that can take out Ghost-types for other physical sweepers like Heracross or Cobalion.
If the Pokemon in this rank have any flaws, those flaws are thoroughly mitigated by their substantial strengths.
...what are Snorlax's flaws? The only "flaws" I can think of are that it has "poor" typing, "weak" physical defense. On the defensive end its poor typing is made up for by its substantial special bulk. It only has one weakness to fighting, and this is easily balanced out by Pokemon like Cofagrigus or Crobat. Not to mention stuff like Cobalion or Scrafty might switch in expecting a weak Body Slam, but might instead eat a CB-boosted Earthquake or Return. Its offensive typing is "poor" because ghost is immune and Steel resists, but Crunch and Pursuit on the offensive end can nail ghosts, while Earthquake and Fire Punch can take out steel. If you're using the ResTalk set, it isn't that hard to predict the switch and just phaze them back out. Its "weak" physical defense isn't even that weak 65 Defense behind 160 HP isn't that terrible, and this is assuming we aren't boosting it with Curse. I Think Snorlax's flaws are thoroughly mitigated by its strengths, and it deserves to move up to S-rank.