Originally Posted by Fat cim
That's not what S rank means.
Regardless, I'm skeptical whether the Pokemon I mentioned are effective enough to be worthy of 'S'. Yes, they are great, but they all have some pretty hard stops, and arguably don't influence the metagame as much as Roserade or Chandelure, who are A-ranked.
I contend that Mew and Heracross tower over the other S-Ranked Pokes in terms of splashability, flexibility, influence, and overall usefulness. Snorlax is really the only thing that comes even remotely close to them.