With Scarlet Enclave now being on the PTR, and set bonuses for the new sets having been made public, there are a few things about the resto shaman bonuses that are odd.
2p
The 2p bonus isn’t scuffed, but just odd. 40% is very high, which is good, but instant cast healing waves (that already cast at around 1.5 seconds) don’t really seem necessary. We’ll see how it plays, I guess, but vanilla content isn’t really known for requiring movement, so this turns a 1.5 second cast into a cast with 1.5 seconds cooldown, while you stand still.
4p
I think it’s really good that Shaman gets a beacon, because they are more or less the designated tank healer for horde. This is a good bonus, and I’m glad blizzard listened to feedback here. However, there is absolutely no reason to put the buff on spirit of the alpha. Other than spirit of the alpha being one of the most cringe names for anything in any game ever (there is no such thing as an alpha wolf), there are two problems with this. First, this forces every shaman in the game, regardless of spec, to use the alpha rune. This is the same issue as with shamanistic rage, but worse. Second, this forces resto shaman away from ancestral awakening. While ancestral awakening was very weak at first, it is becoming increasingly powerful with gear. The rune is now permanently removed from the game, when it is finally becoming useful, and we are left to use a hotfix for broken tank threat instead.
It would make substantially more sense to have this bonus on earth shield (you can even pretend that this was intended all along, and you definitely didn’t want to put it on alpha, like you did with the t3 6p bonus 
).
If this set bonus is not called “beacon of dog”, then you need to sit down and think about life choices, I swear.
6p
As per my previous point, shaman is the designated tank healer for horde. This is because mages exist, so there is no reason to ever heal the raid, and because chain heal is one of the worst spells in the game. While this may sound surprising to anyone who only knows resto shaman from ERA servers, here is a brief explanation:
Mage healers can heal 20 people at a time, with virtually no range constraint, and their throughput is functionally only limited by how much damage the raid takes. This is demonstrated quite well on sapphiron, which can be solo healed by a mage. If there is a mage healer in your raid, there is never a reason for any other healer to use any aoe healing spell, outside of niche cases (like the mage being ccd). Further, druid and priest healers have functionally unlimited range on their aoe healing spells, so if no mage healer is present, they can easily heal the raid.
Chain heal has a range of 10 meters, and this leads to huge issues. If you use it on a tank, then in many cases it will not jump at all, making it a really bad single target heal. If you use it on a range dps, it is very unlikely that it will jump, because range dps HATE standing next to other people. Sometimes, this is even enforced, like with kel thuzad. The only thing that chain heal can do effectively is heal melees, but an efflo will do that too, at a much lower cost.
Chain heal isn’t bad because it doesn’t jump enough, and it isn’t bad because the heal drops off too quickly. The throughput is actually pretty good already. It’s bad because the range makes it useless in most situations, and almost every other aoe healing spell is just better. The only exception is prayer of healing, which is somehow even worse than chain heal. Slapping more throughput on a spell that is bad because of things completely unrelated to throughput won’t fix it. Unless you make the first hit so strong that chain heal replaces healing wave as a single target heal, I guess.
Therefore, the 6p bonus of this set gives tank healers a buff to a spell that they should not be using in the first place, and doesn’t fix the fundamental problems that make the spell bad.
It honestly feels like blizzard has absolutely no idea what to do with resto shaman (which has been a consistent theme in SoD so far), and someone on the team keeps saying “wasn’t chain heal really cool? let’s make them use that!” over and over again, without understanding why chain heal was good in ERA, and why it sucks in SoD, while someone else wants to make them tank healers (as they should be). A far better 6p bonus would be something that actually improves tank healing, such as giving healing wave a 10% absorb shield when it heals, or giving that shield to the beacon of dog target, which would make it more similar to paladin 6p.
tl;dr:
2p bonus sounds a bit odd, 4p bonus should be on earth shield, 4p bonus should be called “beacon of dog,” “spirit of the alpha” is a really stupid name, and the 6p bonus should be replaced with something that increases two-target healing, or at least single target healing, instead of increasing throughput of a spell hat doesn’t need a throughput buff.
Stop trying to force shamans to use chain heal, if you are not going to fix the core issues of chain heal. Just let us be tank healers.