Originally Posted by Fat ElectivireRocks
That's what a wall is supposed to do you know.
Just like water types in OU are usually worthless as long as Ferrothorn is around.
And it's simply not true that many pokemon can't do anything back to Chansey. Anything with 101 subs and a setup or status move can easily use her as fodder, giving you momentum.
Can you really say any other wall in a balanced metagame walls as much as Chansey does? Walling Pokemon is what a wall is supposed do, but the keywords of that quote you have of mine are "a large number of Pokemon." Cofagrigus can check nearly any Fighting-type (gogo Scrafty), but it, 1) doesn't wall the majority of physical attackers because, 2) it is much easier to break due to lower bulk and lack of recovery. But honestly, as many users have stated, its walling abilities, while more impressive than any other wall, aren't the direct reason it's broken. Its use as a crutch as outlined by FlareBlitz and its weight on the metagame as outlined by both kokoloko and myself are the biggest reasons it's broken.