OoC > Berserk by a long shot.
Most optimum solo build at 70 imo is
Talent Calculator - World of Warcraft and then picking up Berserk and going back for the other tanking talents if you want to tank (if you plan to do more than OT you're going to have to respec out of Predatory Instinct to make sure you can fit the rest of the core tanking ones).
You won't be FBing often so RnT won't be much good to you except while tanking, and our TPS is pretty good on the way up regardless, so it's not a big deal; Shredding Attacks is definitely more a raid dps talent (though the cheaper Lacerate doesn't hurt); KotJ...I guess you could take it, free 60 energy every 60sec, but eh. I took Thick Hide because you get the bonus even in Cat, which helps reduce damage taken. ILotP means you can grind endlessly, I never have to stop and heal now with that and Lifeblood.
You should be able to tank instances fine with this spec, and can even get Survival Instinct early if you want an oh shit button (handy for the occasional bad pull when soloing as well as when things get rough tanking).
They're already predownloading 3.1 as of this past tuesday though...I get the feeling it's coming sooner than later. Why are you trying to beat 3.1 to 80 anyhow?