Quick delivery, Blizz. You're fixing something I pointed out only yesterday.
Seriously, though, these decisions are discussed back and forth, and they've probably decided them a week ago. Warning: Some of the links here will be broken when they make the change on wowhead.
1) Unrelenting Storm – reduced from 5 points to 3 points. Bonus is 4/8/12% of your Intellect returned as mana.
A good buff. 2 more points freed up, and more mana to play with. I don't mind.
2) Elemental Warding – now reduces all damage (not just Nature, Fire and Frost) taken by 2/4/6%
Handy. Now it's definately a talent I'll take next time I'll respec elemental. 6% less damage taken will aid me more in PVP and soloing than 3% more damage done will. Raiding might be a different matter. It's perfectly skippable, but it's a much better option now than earlier.
3) Elemental Shields – this talent has been removed, since its effects were combined with Elemental Warding.
4) Storm, Earth and Fire – reduced from 5 points to 3 points, but keeps around the same net benefit. In addition to current effects, also increases Wind Shock range. The damage bonus to Flame Shock has increased to 60% at 3 ranks. Storm, Earth and Fire has been moved up the tree as well.
As I said, the talent was a bit lacking for a 5-pointer. The Wind Shock change makes a lot of sense. The next part, will it be mandatory? If it's no longer a prereq for Thunderstorm, perhaps it'll be skippable for those that don't like it?
5) Shamanism – this is a new 5 point talent in the old Storm, Earth and Fire position. Your Lightning Bolt and Lava Burst gain an additional percentage of your bonus damage. We have not finalized the numbers, but it will probably be something like 10% for Lightning Bolt and 20% for Lava Burst at max ranks.
A talent similar to Druid's balance talent Wrath of Cenarius. But the numbers have a quite different thinking. I imagine Starfire got 20% and Wrath got 10% because of their casting times, 3.0 sec and 1.5 sec respectively, with Starlight Wrath, disregarding any procs from Nature's Grace.
With elemental shamans, you have a slightly different toolbox. With Lightning Mastery, Lightning Bolt has a 2.0 sec cast time and no cooldown, while Lava Burst has a 1.5 sec cast time and 8 sec cooldown. What does this tell us? That they aim for a different goal, namely make us use Lava Burst at every possible cooldown, while boosting elemental shamans' base dps by a less amount. Makes +hit gear even more important, as a few missed Lava Burst really is going to hurt.
I'm also wondering why they don't give any benefit to Chain Lightning. They have earlier stated that they want elemental shamans to have the option of doing some AoE, like other caster dps. If so, why not buff Chain Lightning a bit as well, not just the totems?
Shaman – we are removing the threat component from Fire Nova Totem and Magma Totem and increasing the damage from Magma Totem. This should provide the Elemental shamans in particular with some formidable AE.
I assume this means the "additional threat" component of the two totems. They'll still generate normal threat, or it'd be slightly broken. At least while soloing.
Some people argued that it wouldn't be worth it since you couldn't use Totem of Wrath at the same time. Ghostcrawler answered:
But the change to Magma Totem in particular is substantial. The base points went from 170 to 370 and the coefficient from 0.67 to 1.0. In our tests, the pulses were doing something like 600 damage. You would be hard-pressed to get that kind of increase out of Totem of Wrath, even considering its benefit to the whole raid.
In addition to what he says, there's also the raid stacking to consider. Dwarf Priest wrote an excellent guide. If we look at it, we see that Totem of Wrath is considered among the best available spellpower buffs, but tied with Demonlogy Warlock's Demonic Pact, which doesn't really go away. So you may not loose a lot of spellpower. On the other hand, the spellcrit debuff isn't so easily available. A tier 2 paladin talent Heart of the Crusader duplicates the effect, but on one target only, for the duration of a judgement (10 seconds). And when would you lay down a Magma Totem in the first place? When you need AoE. AoE = Multiple enemies, so a single, or even three or four judgements doesn't really replace the effect.
The good part, though, is that Magma and Fire Nova totem has threat of their own, so if they overaggro, you just lost your mana investment, while you retained your life. Unlike certain other AoErs.