I'll just go ahead and quote myself here.
To elaborate on that, you bothered to take Imp Shapeshifter, which is 5 points for a 4% damage buff, but think that Rend and Tear, an approximate 11% damage buff while tanking, isn't good enough. Here is a WWS to support that statement, and this was in horrible gear and a very low crit on Maul, with it being 10% under expected crit rate. Factor in that Maul is our best scaling attack, and will soon be 60-65% of our total damage, you cannot possibly say that Rend and Tear is too weak.
Counterpoint: As an OT, I much prefer the spec I posted. As a MT, you will probably want R&T. The reason being, in a 5 or 10-man, you're doing a ton of swiping. R&T doesn't apply to swipe, and often putting up bleeds is a waste of time on trash. Moreover, unless you run with a second feral or an arms war, or a hunter with that specific pet, no one else is gonna bleed anything for you. On boss fights, your threat should be through the roof, and you suffer a very small damage penalty.
Here is a WWS of a KT kill; I dps'd to 40%, picked up all 4 adds. Now, obviously this isn't gospel because the numbers are clearly skewed (I didn't record the WWS, no idea why it picked up multiplied values for swipe and maul a couple of times) but even if you completely subtract out all of the skewed hits, I am still 4th or so.
Now, here is a WWS of dps on Sapphiron. This is a great OT spec because it allows you to still pull 3k+ dps even in non-ideal fight, and even allows you to switch rolls mid-fight.
I wish I had better reports to back it up, but it's been a week, so its hard to pull numbers right now. Plenty of recount parses back it up, though.