>>32540320Rock is a Slow Mixed Physical type. If you average all rock type Pokemon, you end up with decent HP, good Atk, good Def, bad SpA, decent SpD, bad Spe. This lends itself well as a physically offensive typing, able to hit hard, and generally able to survive one physical SE hit in return (or a few neutral hits).
The biggest problem is that more of Rock's weaknesses come from special attacks like Giga Drain or Hydro Pump, and rock tends to be paired poorly with secondary typings, most often gaining more weaknesses than resistances, and there's no definitive typing that would negate or significantly diminish the five weaknesses rock has.
