Stat Priorities
Raid
Intellect > Critical Strike > Versatility = Haste > Mastery.
Mythic+
Intellect > Crit = Versatility = Haste > Mastery.
Stat Outline
Critical Strike: Critical Strikes give us mana back if talented into Resurgence and increases output when we land a crit.
Versatility: Increases our healing and damage by a flat amount and reduces the damage we take by half of that.
Mastery: Increases our healing done to targets based on their current hp, the lower their health, the more healing we do.
Haste: Most of our abilities don't scale with haste which makes it relatively weak, especially in a raiding scenario. It gets more important in dungeons, specifically for single target damage.
Races
I want to preface this by saying that picking a specific race is around a 0.5% increase, so if you’re not super into minmaxing, then there is very little downside to just choosing what you like playing. That being said, Stoneform for M+ is very powerful, so would be the only reason I would specifically recommend playing Dwarf on a Shaman.
Dwarf - The best race for Mythic+ content by far. Might of the Mountain is a strong passive DPS/HPS increase, which scales with the amount of critical strike we get throughout the expansion. On top of that, Stoneform is the biggest game-changer defensive racial that can completely negate some mechanics.
Tauren - Just like Dwarf, Brawn is a strong passive DPS/HPS increase, which scales with the amount of critical strike we get throughout the expansion. On top of that, Endurance helps with one-shot mechanics thanks to extra stamina, while War Stomp brings additional CC potential.
Pandaren - Gives huge output increase thanks to the double effect of the food buff.
Orc - A Decent on-use, you can easily macro into one of your cds, giving you some spellpower and some more power when needed, not super powerful, but decent.
Goblin - Used to be extremely important for shamans, thanks to Rocket Jump. It helped a lot with some mechanics/mobility. Thanks to the new talent tree and return of Gust of Wind, a goblin is no longer required, and we can opt for a more throughput-oriented choice.
Enchants
Cloak: Chant of Leeching Fangs
Chest: Council’s Intellect
Bracers: Chant of Armored Leech
Boots: Defender’s March
Legs: Daybreak Spellthread
Rings: Radiant Critical Strike
Weapon: Authority of Radiant Power
Gems
Diamond: Culminating Blasphemite
Other Gems: Versatile Ruby or Deadly Sapphire
Consumables
Food: Feast of the Midnight Masquerade
Phials: Flask of Tempered Aggression
Potions: Algari Mana Potion
Health Potions: Invigorating Healing Potion
Weapon Oil: Earthliving Weapon or Algari Mana Oil
Runes: Crystallized Augment Rune