If we assume that the 2T8 feral bonus procs as often as OOC and that you have 100% uptime on both Rake and Rip (not realistic, but this is just an initial look) you'll get about 2.9 more procs per minute (35/12 to be exact). If you convert each proc into a Shred this will equate to 122.5 energy/minute. Realistically you can probably plan on about 100 - 110 energy/minute.
I believe 2T4 could proc on yellow attacks. If so, assuming you did 90 total attacks per minute you would get 3.6 procs for 72 energy/minute. It was strong enough that dps ferals still used it in Sunwell and it had to be nerfed in order to keep us from using it in WotLK, yet now 2T8 appears to be even stronger. Either it has to proc less often than OOC or T9 will have to have very powerful bonuses.
Eh, more like it's a boilerplate tooltip, and they added "until canceled" as the duration. In any case, it's not gonna be until canceled, that would set up some very interesting issues in PvP. I wouldn't be surprised at a 10s buff, though, single charge. Regardless, that will once again muck with theorycrafting, but it's a very powerful set bonus.
Item - Druid T8 Feral 2P Bonus (Class: Druid) -- The periodic damage dealt by your Rake, Rip, and Lacerate abilites has a chance to cause you to enter a Clearcasting state.
Item - Druid T8 Feral 4P Bonus (Class: Druid) -- Increases the duration of Savage Roar and Survival Instinct by 8 sec.
Didn't they learn? The T7 set had bonuses that only benefitted either cat or bear. After some months they finally changed it so each bonus gives something to both bear and cat.
The T8 2p bonus seems decent enough for cat, but it really needs something for bear too (couldn't care less about clearcasting while tanking). T8 4p bonus seems very nice, I'd be very surprised if optimal feral set doesn't include 4 T8 pieces (unlike T7 currently).
* Enchant Weapon - Blood Draining *New* - Permanently enchants your weapon to sometimes grant Blood Reserve when striking an enemy or inflicting damage with bleed attacks. When you fall below 35% health, Blood Reserve restores 1750 to 2250 health. This enchantment requires the wielder is at least level 75.
Assume this would be the new "Druid" tanking enchant. It's unclear from the description what it does (if anything at all) above 35% hp. I'll see if I can track it down on PTR and get some testing done.
edit: I speculate it gives you a buff when it procs (can proc whenever), said buff just sits there and does nothing until you fall below 35% at which point it restores the hp and disappears.
Enchant Weapon - Blood Draining *New* - Permanently enchants your weapon to sometimes grant Blood Reserve when striking an enemy or inflicting damage with bleed attacks. When you fall below 35% health, Blood Reserve restores 1750 to 2250 health. This enchantment requires the wielder is at least level 75.
A new enchant arriving, what do you think, is can be good for tanking, or too small amount of heal to be usable?
About the T8 feral bonus: i feel them to weak a bit, or at least insignificant for tanking. As i see they try to give not too powerful bonuses, to avoid the 2pieces-T4 problem, but because this we get glyph-level plus, what i feel a bit less when i compare an 2-3-10g price glyph with a 2 or 4 pieces armor from the actual high-end content.
Feral 2 piece is pretty worthless for tanking unless the boss actually causes you rage issues. It can be really good for dps, depending on proc rate
I have mixed feeling about 4 piece on tanking, since SI is not damage reduction. However it also lasts longer than barkskin (both base and bonus duration) so that's good. For DPS it i guess can make fitting FB in more easily now.
The feral bonuses look very, very good for catform. A 4pT8 would greatly alter the most efficient rotation; it would be a 1/2CP SR->Rip->FB, most likely. With the glyph of shred and the glyph of rip a 22-second rotation would be pretty feasible, which would basically add an FB every 22 seconds as damage. That's very strong.
The 2-piece, as Melthu indicated, is potentially strong enough (and would scale well enough with all future gear) that I can't see reasonably removing it unless the bonus is simply that poor.
Neither is particularly compelling for tanking. The SI bonus is simply subpar; gaining 8 seconds for a cooldown only used in emergency situations means that you'll have a huge amount of health for 28 seconds instead of 20 seconds. How is this going to be significantly useful? And it's applicable to both cats and bears as well. The other bonus is not. Just...disappointing, all around.