I've been thinking a lot about this, and for the most part, I think this change is awesome. The major downside of 90% of Rock types has been their frailty in the face of special attacks, especially Surfs and Grass attacks. So this gives them a fighting chance. I mean, start with the ADV tier list - how many Rock types are OU/BL? 5. Rhydon still has gay special defense, Aerodactyl still dies to most anything (and is hurt by Stealth Rock now), and Armaldo was never particularly amazing and now might find its way into good OU, which is awesome because Armaldo kicks ass.
Then there's Regirock... honestly, Regirock will probably still have its problems, granted you could use a Curserock but I bet it will still end up being Garchomp fodder, imo.
Rhyperior is kind of potent, but hardly invincible. Surfs are going to do it in good, and 90% of fast Pokemon are capable of getting in a good hit on it - Rhyperior is not going to sweep teams, plain and simple. Trick Room/Rhyperior combinations might show up, but I doubt those are going to change everything.
Tyranitar is a pretty big problem though ;[ I dunno, I guess we need to test it and see what happens, but we're already looking at a 660 stat total and Tyranitar has a great movepool. The only thing separating it from most ubers is a ton of weaknesses, so we'll have to see whether that balances it out.