2-piece: Increases the bonus granted by Eclipse for Starfire and Wrath by 15%.
4-piece: Each time your Insect Swarm deals damage, it has a chance to make your next Starfire cast within 10 seconds instant.
This is final confirmation, as if any were needed, that Blizzard is balancing around raiding moonkin using Eclipse. Graylo had a look at the tier set when the 2-piece bonus was only 6% and wasn't tremendously impressed at the time, but with the damage bonus buffed to 15%, at least you're not actively losing damage going between 4-piece Tier 7 and Tier 8 anymore.
Verdict? 2-piece is OK, especially if you're religious about managing your Eclipse procs. I don't know how good the 4-piece bonus is yet, and I'm prepared to see a torrent of complaints on the forums that it's competely worthless if your Starfire rotation has just procced an Eclipsed Wrath damage increase, or that it doesn't proc often enough, or what have you. So far I haven't seen any solid information from anyone on the PTR as to the likely proc rate (no surprise there, as I doubt anyone's running around in 4-piece Tier 8), so stay tuned.
2-piece: The periodic damage done by your Rake, Rip, and Lacerate abilities has a chance to cause you to enter a Clearcasting state.
4-piece: Increases the duration of Savage Roar and Survival Instincts by 8 seconds.
Amazing for cats. Garbage for bears. The cat DPS rotation (insofar as never letting any of several debuffs drop could be called a rotation) is very difficult, and an additional 8 seconds on Savage Roar plus the chance of a Clearcasting proc is huge.
For bears, both are underwhelming, especially once you've seen the Warrior 4-piece Tier 8 bonus. For raid tanking, you're generally not going to face a low-rage situation, and this is all the more true once you factor in the armor nerf and rage gain even while shielded. An additional 8 seconds on Survival Instincts falls pretty squarely into the category of "nice," but not exactly game-breaking. You'll be using Tier 8 for the stat bonuses over Tier 7 and certainly not for the set bonuses, although the transition should be relatively easy because Tier 7's set bonuses are also kind of meh.
2-piece: Increases the healing done by your Swiftmend spell by 10%.
4-piece: Your Rejuvenation spell also provides an instant heal for the target.
Both are very welcome, especially in conjunction with Glyph of Swiftmend and Glyph of Rejuvenation, as I assume the latter will apply to the instant heal as well. The Swiftmend bonus...well, that goes without saying. If you can pull it off without allowing the bonus to go to +overheal, this is a solid plus. But again, when it comes to 4-piece bonuses with procs, there's really not much information out there yet, so I don't know how much the 4-piece bonus heals for or its exact mechanics. I assume it applies an instant heal on the initial application of Rejuvenation, which may prompt you to reapply Rejuvenation on a tank earlier than you might have otherwise, or to use Rejuv even more than you already are as a raid heal.
What I find most interesting is something Ghostcrawler's previously noted concerning Blizzard's own data on Ulduar raids; they're seeing Rejuvenation continue to be the single greatest contribution to healing done by Restoration Druids, so this is quite a lovely bonus.
What profession changes are most likely to affect us?
Alchemy: As we already know, flasks are only going to last 1 hour (2 hours for Alchemists with Mixology) but be cheaper to create but be cheaper to create. You're less likely to have to "waste" a flask if your guild is 3/4 of the way through a raid night and decides to try more new content.
Jewelcrafting: Finally, finally, FINALLY we are getting an agility/stam cut, which was arguably the single best purple gem for bears in Burning Crusade but never made a reappearance as a Superior-quality cut in Wrath. For cat DPS, you're going to want to go back to agility and agility/hit gems for maximum DPS sets, as Savage Roar now increases your physical damage and doesn't bloat your attack power.
Enchanting: There's a fantastic new enchant for tanks called Blade Ward that, once procced, increases your parry rating by 200 and will cause 600 to 800 damage on your next successful parry. Better yet, it can stack up to 5 times and the effect lasts 10 seconds. This is amazing, and it's a great boost for both avoidance and threat generation. In related news, bears are still unable to parry.
How is Savage Defense working so far?
I've done my own testing but basically arrived at the same conclusions that Kalon of ThinkTank did. I tested it against mobs for dailies and then a random collection of elites I ran around pulling in Icecrown, but haven't yet had the chance to test it in a raid (for the few PTR fights I've done so far, I've gone as Resto).
It's a buff versus multiple low-level enemies that don't hit for squat, which dovetails pretty neatly into Blizzard's intent for it to function as a pseudo-version of block. Versus Icecrown elites you'll notice unshielded hits that do land will hit for more, but not memorably so; I finished with about the same amount of health as I did on live, give or take some RNG either way. Outside of a raid, you probably won't notice much of a difference, and I will hesitantly say that for the most part it will also be a buff to our survivability on heroic trash.
However, it's precisely the RNG that's the real issue here. The jury's still out on how this will help (or hinder) our status as potential main tanks on Ulduar content, because the shield can't be triggered by anything other than a crit.
Daveorn on the Elitist Jerks board makes the point more succinctly than I've seen it put elsewhere: "A weak blow (could theoretically) pose a serious threat to my survival by stealing the SD absorption before a large hit lands." I'm additionally concerned because sources of bear attack power are pretty thin on the ground, so the size of the Savage Defense "shield" may or may not scale all that terribly well. The only sources of strength for us in Wrath raids are non-set pieces that we share with (and are often better itemized for) plate tanks, and we're otherwise dependent on the raw AP that comes with our pieces. Ideally I'd like to see bear attack power scale with agility, but I don't know that we can expect that.
We're going to have to start using Nourish, aren't we?
That's a big 10-4, good buddy. And if you're one of the many Resto Druids who has eschewed Tier 7 in favor of better individual pieces elsewhere because our 4-piece bonus to Nourish was kind of worthless...it's less worthless in 3.1. Start pestering your raid for those Vanquisher token drops now if you haven't.
What do Ulduar bosses look like so far? Are these fights good for Druids? Bad for Druids?
Once I have a better sense of what's happening on the European PTR's, I'll have an article on this. At the moment, my sense of the actual fight mechanics there is unfortunately fuzzy at best.