My guild currently has cleared the first four bosses in ICC, we haven't tried the new wing yet. I just recently picked up the 2 Piece Tier 10 (Gloves / Shoulders)
I plan to start working on the 4 Piece next, thinking maybe Legs / Chest. Now because of this I was wondering if it would be worth dropping the 2 points in Primal Precision and the point in Omen of Clarity after I get the 4 piece, and putting those 3 into King of the Jungle making Enrage a 30 Rage gain, 12% reduced damage, 15% increased Damage button of awesomeness.
I was curious what other druids plan to do once they get their four piece.
One thing you are neglecting however, a tank doesn't really care about their damage, so long as they generate sufficient threat to stay above the DPS in threat. Primal Precision is a survival talent since it reduces parry hasting by improving expertise. So a pure tank would like still choose to ignore King of the Jungle, while you're tanking it's not your job to top the damage meter, it's your job to top the threat meter (and to be able to survive being there). So long as you are doing that, you are serving your raid purpose.
I'd say ignore King of the Jungle unless you are above the parry cap for expertise without Primal Precision. If you're above the cap I guess you could consider it.
King of the Jungle will never be as good as Primal Precision on a per-point basis. At best, KotJ is 1% more threat per talent point; at worst, primal precision is 1.25% more threat per talent point as long as you're not expertise-capped (and you won't be).
Don't get the T10 chest unless you want it for cat and bear. Ikfirus' sack (which is BoE, so you'll be able to buy it) is exceptional for bears. Get the legs (whcih have expertise) and the head.