Originally Posted by Fat Snunch
Offensively, it can't break through common walls
Wut? You clearly have never tried him. All he does is break through common walls. If you're trying to Head Smash a pokemon with a Rock resist on the set that I gave with so many other options, you're doing it wrong.
Also, Aerodactyl can't take a CB STAB Frustration either. He also happens to be weaker offensively, and with much of his speed wasted in UU tier.
Also, Rhyperior can't even reach decent speeds with a Scarf, he needs to spend a turn on Rock Polish to get there. He also has 25 less base Attack. If you want to even get close to the power of Head Smash, you have to use Rock Wrecker, because Stone Edge has 50 less base power. Rhyperior might be able to wall normal hits, but he's weak to just about everything else a physical or special attacker can do.
Also, all three of the Stealth Rockers you mentioned also get shut down by Swampert and Hitmontop.
I don't think any of your points are relevant. I'm not trying to say the pokemon you mentioned are bad, they have their uses, but Rampardos does too, and he isn't strictly outclassed by any of them.