Heh, that's kinda funny actually. You're pumping speed over defenses because it's safer. I can't say that it's not a good idea, but there's an irony there. I don't see how Skarmory stands to counter Rhyperior, but outspeeding Weezing and Slowbro is certainly valuable. I did some math and got 172 EVs as a good number for fast Rhyperior to use since it's a sure thing against non-Timid Slowbro, and it still outspeeds min speed Weezing by 3 points.
However, about defensive Rhyperior, he seems like something that I thought might not exist. He seems like a Tyranitar counter. With 252 defense and not that much HP(or just a +defense nature), Tyranitar's only means of getting a 2HKO is Focus Punch, and that's CB Focus Punch. DDtar and boah and pretty much everything you can come up wtih except CGtar(with HP grass/water) is just steamrolled by Rhyperior. I was thinking of Quakeedge+Resttalk, and no there's not any real risk of getting Sleep Talk Taunted as one DD on ttar isn't a big concern. You should OHKO all CBtar, and if you have max attack adamant, you'll OHKO max HP min def ttar pretty often(with EQ of course). A lot of this depends on how the DP metagame turns out. That defensive Rhyperoir does run into serious trouble with both Garchomp and Gyarados, and CBgross's Meteor Mash wouldn't be a wonderful time. It would also lose to CB Rhyperior unless it was stuck on something not Earthquake. That might be too much of a liability for anything that wants to try to focus on physical defense, but perhaps being able to switch in on Tyranitar is quite appealing. Being slower than ttar could be a liability, but you have the boon of scaring ttar with a potential OHKO so that might not be so bad.
Yeah, I definately agree with the overall sentiment of the topic with the whole "wow, Rhyperior is really amazing". This thing could very well end up being as much of a staple of the DP metagame as the feared Garchomp; it hits harder and takes hits better at least.