A lot of people agree that Shaman is weaker than Beastmaster and Druid and that it is in dire need of a rework.
One huge missed potential I find with Shaman is Mana and specifically Attunement.
Shaman can hit 52 Attunement with just base passives and the class bonus but what is this bonus good for? a pinch of increased damage on skills and increased freeze rate multi on few spells, poison chance on a couple of minions… Maelstrom has a node that gives it 40% more damage at 60 attunement but there is no reason to stack attunement past that.
There are two major attunement stacking builds Judgement Paladin and Frostbite Swarmblade. It just seems odd that the main Attunement class does not have any good Attunement stacking synergies.
Attunement also gives 104 mana and there are other nodes in Shaman for more mana and mana regen. But what is the point of all this mana and mana regen?
Mana regen gets easily outclassed by mana generators if you want to spend mana, since there is no source of Flat mana regen.
Shaman also has no real use for a large mana pool. In comparison a Sorceror has damage absorbed by Mana, ward gained per mana used, ward gained for using high cost skills, etc. Even Marksman has some increased damage based on mana cost and mana consumed.
Adding some more Caster/Mana based synergies may be good for Shaman(especially since main Primalist defenses are based around melee). Maybe even better to ditch the whole melee/caster schtick and just make Shaman a powerful ranged alternative to Beastmaster/Druid.