Please note that if you've been using my old Need To Know post, the information found in there is still relevant for a fresh level 90. The purpose of this particular post is to expand upon the new talent tweaks and how they may interact with gear from Throne of Thunder.. If you're a fresh level 90 and/or just returning from the spirit realm (aka if you haven't played your shaman since Cataclysm) I highly suggest going back and reading my Need To Know post linked in this paragraph.
As has been noted in the 5.2 Changes for Shaman post, several talent tweaks have been made. With these adjustments in mind, the following is more or less how we should think about our talent choices.
Elemental Mastery - Best used in burst situations and becomes more valuable during fights where our damage uptime may be a bit low (numerous target switches that cause downtime; controlled dps situations such as Titan Gas phase on LFR/Reg Will of the Emperor, or the no add lull on H-Will of the Emperor)
Ancestral Swiftness - Best for static (Patchwerk) fights. The higher uptime on a boss, the more this talent shines. Used mostly with haste builds, which will become more widely used once one acquires the legendary meta gem, along with trinkets from Throne of Thunder.
Echo of the Elements - Still the best talent choice for those who are leveling, as it can proc extra healing. Also a very solid choice for soloing in my personal opinion, again due to the chance for extra "free" healing. For competitive raiding, this talent is best when paired with mastery stacking and will shine more during AoE/cleave encounters.
Unleashed Fury - This talent received a slight nerf in this patch to help bring it more in line with our other two talent choices, but the nerf bat wasn't too harsh. For those of you who are still fresh level 90s/sporting t14 gear, this will still be your best overall talent choice. With this particular talent, it seems that mastery will still be your favored secondary stat.
Primal Elementalist - PE received a pretty decent buff in this patch to help it compete with Unleashed Fury. Our elementals now provide some fairly substantial burst (they did a good bit before as well, but now it's really solid), enough to the point where they'll make up for the lack of damage during their down times. This talent is my personal favorite for soloing, but unfortunately may not be the best choice for general raiding purposes until you have acquired your Capacitive Primal Diamond, plus have gotten your mits on Talisman of Bloodlust and Bad Juju. This talent *could* be useful on controlled burst fights even with current gear, however. This is of course assuming that phases of whichever encounter you're tackling line up properly with the CDs of your totems.
Elemental Blast - Like Primal Elementalist, Elemental Blast has received some love to help make it a more enticing talent to take as Enhancement. In addition to proccing extra secondary stats, EB will also proc Agility for us. Pretty neat, eh? As it stands right now though, EB is still a touch behind the other two talent choices. It's viable for use, don't get me wrong, but it is still slightly behind. Couple this minor negative with the fact that it still has a cast time (which can be negated if you have a Maelstrom Weapon stack of x5, but if you don't you'll be hardcasting), that you'll have yet another button in your already button-heavy arsenal, AND you'll have another minor CD to watch (12 seconds, so not all that different from our other rotational CDs like Lava Lash and Stormstrike), EB still remains to be a less than desirable talent for most shaman. Essentially it complicates an already somewhat hectic rotation for no actual DPS gain over the other two talents. However, if you're a diehard fan of this talent for whatever reason, you still may choose to spec into EB and not have the fear of severely gimping yourself on the meters.
Talent Choices, Secondary Stats, and You
One of the more common questions I see coming from fellow Enhancement shaman is thus:
I'm ilvl 461. How should I gem/reforge? How do I spec?
The common answer is often "Well, you're going to have to sim it." This answer is unfortunately both completely true, but can also be rather frustrating to someone who isn't familiar with either theorycrafting or the program Simulation Craft itself. The fact of the matter is, two Enhancement shaman may both have an ilvl of 461, but they could very well have a large variation in stats. One may be really heavy in Critical Strike, while the other could be Mastery heavy. A third shaman may very well have a balance of all three non-mandatory secondary stats, but is starving for things such as Hit and Expertise. Early on in the gearing process, Critical Strike can actually outweigh Mastery and Haste, because of how the synergy between the different stats works out. As you gain more gear though, Crit tends to depreciate in value, making way for the power houses that are Mastery and Haste.
Bottom line, if you're looking to min/max your shaman to the greatest extent, you will need to learn how to run Simulation Craft, aka SimC. Luckily for you, Poneria did up a post on WoW Insider about Simulation Craft. Don't balk at the fact that it's actually a warlock post; there is a ton of excellent information and links in that post to help get you started with SimC. It's a definite must-read for those who wish to push themselves a bit further.
For those of you wishing to merely get by without having to dip your toes into the wacky world of theorycrafting, there is are a few rules of thumb that you can follow to make yourself at least competitive in regards in how to gem, reforge, and spec your Enhancement shaman.
Gems: You can stick with whatever gems you had in your level 85 gear. Most leveling gear is socketless, so you don't need to worry about this much.
Reforging: Not necessarily something you need to worry about much. You want at least some hit and expertise to make life a bit easier for you; more mastery while leveling is quite handy.
Speccing: As far as the DPS talents are concerned, Echo of the Elements (for those wonderful double Healing Surge procs) and once you hit 90, Unleashed Fury will be your best bets. All other talents are more based on preference and situation.
Fresh Level 90s
Gems: Delicate (pure Agility gems) in red sockets, Adept (orange gems, Agility/Mastery gems) in yellow sockets, Deft (purple gems, Agility/Hit gems) for purple sockets.
Reforging: You must first shoot for your Hit/Expertise caps, if possible. If you need to, you can help supplement this with Hit and Expertise enchants. For secondaries, it'll be, as I said, a bit of a toss up depending on what stats your particular gear setup actually has. I personally went Mastery > Crit > Haste on my second shaman while I was working on getting the rest of her heroic 5 man set.
Speccing: For those of you heading into those 5 mans, Echo and UF will still be great choices, since you'll more than likely be putting priority on Mastery, plus the extra chance at AoE procs from Echo (Fire Nova can proc echos) will help out nicely for all of those trash packs.
Gems: As with the fresh level 90s, you'll still be going for straight Agility gems, Agility/Mastery gems, and Agility/Hit gems.
Reforging: Once I started getting a decent base of crit and stopped starving for so much Hit/Expertise on my second shaman (meaning, I was starting to get purples) my priority changed over to Mastery>=Haste>Crit. You'll want to have a healthy balance of Mastery and Haste, as they're both excellent stats to have. I tend to go a bit heavier into Mastery for this particular tier though, especially with often still being specced into Echo+UF.
Speccing: With the new changes, speccing for raiding becomes rather situational. For your level 60 choice, see the Talent Tweaks section earlier on in this post. For the most part though, Unleashed Fury will be your level 90 talent of choice.
This is were things start to get nice and murky as far as secondary stats are concerned. Until you get your hands on the new RPPM* trinkets (Talisman of Bloodlust, Bad Juju, Renataki's Soul Charm, and Rune of Re-Origination are specifically being considered for BiS lists, see this thread for more info), you'll be speccing and reforging just as you had for tier 14. However, the game changes some once you get said RPPM and your legendary meta. Suddenly, with these items, Haste becomes a pretty big thing.
Gems: For those in LFR/Normal mode t15 gear with RPPM trinkets, you'll be most likely going with pure Agility gems, Agility/HASTE gems, and Agility/Mastery gems. If you do not have the RPPM trinkets, the t14 scheme will still be more ideal.
**Note: There is a slight possibility that we may even gemming straight Haste with the new trinkets + legendary meta gem + BiS Heroic Throne of Thunder gear. Theorycrafters are still working out the details on this, as the RPPM trinkets are still being tweaked, but the future possibility is there. **
Reforging: Again, once you get your RPPM trinkets, Haste will take a priority over Mastery. It'll more than likely be a reforge priority of Hit/Expertise | Haste > Mastery > Crit.
Speccing: This follows suit with t14 until you get, you guessed it, the RPPM trinkets. Once you do, your level 90 talent of choice will often be Primal Elementalist. There may be certain situations where UF may still be better, but with all of the Haste procs and stacking going on, PE becomes a delicious source of damage. The level 60 talent choices will be very encounter-based still, so please refer to the Talent Tweaks section of this post for more information.
Please keep in mind that this is an extremely rough and broad guide. Your stat change over points may slightly differ depending on which trinkets you have, which set bonuses you manage to activate, and of course may depend a bit on whether or not you have acquired your legendary meta.
Also keep in mind that each of the three level 90 talents have a slightly different rotation priority. To find out more about that, I highly suggest you read up on the Ability/Rotation section of the Enhancement Guide over on Totemspot.
If you're looking for a Throne of Thunder shopping list, you'll want to keep your eyes on the Enhancement Best in Slot List for Tier 15 thread, which can also be found over on Totemspot. Keep in mind that the list is subject to change, as the TC guys are still working on simming out all of the possibilities, plus Blizzard is still tweaking trinket procs and the like.
The long and short of this post is thus: 5.2 has moved us away from what was nearly a cut-and-dry spec set up as far as our DPS talent choices were concerned, and dumped us into the realm of situational choice. Everything - your gemming scheme, spec choices, and reforges - is dependent upon your particular gear set up and raid encounter situation. From a min/maxer's stand point, this kind of makes things both chaotic and interesting. From the view point of someone more casual, this simply means you have a bit more leeway in choosing how to play.
The difference between talents is rather small now, so you very well could simply choose a combination of talents that you like the feel of and still be rather competitive. If you're not trying to eek out every last drop of damage from your character, you have plenty of room to experiment with. Personally I've been playing around with a high-burst build on my main shaman for soloing situations (it's pretty damn awesome, I'll tell you what!). Would I use my current build in a current raiding situation? Hell no, since I know I don't have an optimal gear set up to make my EM/PE + Haste stacking as competitive in damage as say, being a tad more Mastery heavy and rocking AS (or whatever talent depending on encounter)/UF. Since I'm not raiding for the moment though, it's very fun to toy around with. Sometimes experimenting to see how far your gear can take you in certain scenarios is a very fun thing to do, or perhaps I'm too much of an Enhancement/soloing nerd for my own good.
As always, if you have any questions, comments, or concerns about this topic or anything else shaman related, please don't be shy!
*For those of you who are confused as to what RPPM means, it stands for Real Procs Per Minute. This is essentially the internal system that's in place that determines how certain trinkets and enchants proc. If you want to read up on some of the nitty gritty details of this system, you should check out this series of blue posts.