I kind of like your spec actually. Increasing crit damage from 200% to 210% wouldn't really be that great in PvP since crits are negated a lot anyway. However, I'd probably take the two points out of primal precision and finish off Rend and Tear and Improved Mangle.
http://talent.mmo-champion.com/?drui...00000000000000
Then again, I'd have to actually play some arenas at 80 (with a real team, skirmishes don't help too much) to see just how much AoE comes into play. In BC it makes sense to get this talent because it's a flat resist chance (meaning less novas or AE breaking you out of stealth in bad situations), but maybe not anymore.
If you got Predatory Instincts, however, you could always take the 3 points for Imp. Mangle out of Naturalist, or skip out on Imp. Mangle altogether, although it seems to me that spec'ing Imp. Mangle and mangle spamming for Roar CPs would be the best tactic, then do the normal Mangle->Rake->Shred to 5 and then FB or Rip depending on the target (You'd get CPs a lot faster for Roar with an ability that only costs 34 energy as opposed to 42 energy, and then you don't have to worry about it for a full 34 seconds). Just my thoughts.