As the title describes, resto shaman is in need of immediate attention which needs to come either at a healing percentage buff increase, or a redesign of the current tier set.
Before giving more detailed analysis, I would just like to point out that I am a veteran shaman player, currently ranked top 10 in m+ keys (3100 rio) and top 20 world amongst all healers in keys. Similarly in terms of raiding, we usually finish world 300-400 which means 1-2 rounds of nerfs in mythic bosses, pretty standard not something to brag about.
The issue now is that with the new upgrade system (which I love by the way, I think its very healthy for the game and a step towards the right direction) people have reached or are close to reaching 90-95% of available class power in terms of gear and ilvl, therefore we are seeing everything that classes can bring to the table (Excluding trinket drops).
The current tier set bonuses of resto shaman at best offer a 4-5% increase in terms of throughput. That is with proactive setup as you need a lot of prep to feed the 4-set bonus and to be quite honest it feels clunky, unintuitive and frankly useless. In terms of raids there is no seeming difference but there are a few instances where it is actually useful in m+, since planning in high keys (23-24+) is crucial. The issue however remains that it is miles behind the tier sets of other healers and this is visible from the raid statistics as well. One only has to look into the Mythic Rashok logs for instance where a resto shaman should be able to shine, and it is currently last by miles in terms of throughput. That is fundamentally flawed and should be addressed immediately.
Same thing goes for m+, I can give an example for Halls of Infusion 3rd boss which is a pure healing throughput check. Having timed it in Tyrannical +22, I was getting north of 130-140k hps, with no externals (e.g. Innervate) and of course I was close to running out of mana by the end. I know my class inside out, and I know that the absolute best a resto shaman can pump in that fight is probably around 150k hps and thats it. Seeing an evoker in a 24+ easily pull 190k hps at the end of the same fight and still be at around 50-60% mana is honestly a joke. The raw power that comes from their set bonus is insane compared to the laughable 3-4% increase of Tidewaters which has no reason of being in the game.
I hope that news come soon of a new balancing round, because the healer balance at this point just isnāt there. Resto shaman in my humble opinion needs a tier set bonus overhaul which complements the playstyle and making an actual difference. Being the healing class with the most active spell usages I am certain that there are multiple routes to do so.
These are my 2 cents, I hope for a constructive discussion / feedback.