I have struggled to understand the mechanics of Azerite gear, so these are some notes I made for myself. I am posting them in case they might be helpful to others.
The neck piece
The base part of Azerite gear is a legendary-like neck piece that is the “one Ring to rule them all”. It is earned through a short intro quest line when a player begins BFA and will remain for the entire expansion.
A. It is the repository of Azerite Power (AP) needed to energize three other pieces of special gear. (Conveniently, Blizz is recycling the “AP” term that in Legion stood for Artifact Power, 🙄)
B. The neck piece has two measures of power: ilevel and AP level.
1) Ilevel is the overall gear level, same as for other gear. However, ilevel can only be increased by achieving rep with one of the BFA factions, and at least so far that advancement stops once a player has earned Revered status — Exalted does not advance the neck piece. The purpose of advancing the neck ilevel is probably just to help a player’s overall gear level — a higher level neck piece does not change the collection of AP or in any way affect the Azerite gear the neck controls.
2) AP level is a one-up measure, starting at 1 with a probable endless top level. Many of my guildies are at 21 or 22 AP level now, but I just dinged 20. Your AP level is what determines how many special traits you can unlock on your Azerite gear. (More about this below.)
3) Players gather AP through world quests, mission table quests, and Island Expeditions. In general, the amount of AP awarded from all but Islands is minuscule in comparison to the amount required to advance. (Something like 1-2% of the total required to advance to, say, level 20.)
C. AP in BFA is in itself quite complicated. Blizz claimed they learned a lesson from the ridiculous AP numbers required in Legion, so in BFA they have “fixed” that. (Editorial comment: not so much.)
1) First, a history lesson as background:
a) In Legion, Blizz decided that the amount of AP needed to advance one’s artifact weapon would increase almost geometrically with each new level. That is, if it took, say 800 AP to advance to level X, it might take 1200 AP to advance to level X+1. The problem with this was that by the time a player was well advanced in their artifact weapon, it could — and did — require a trillion or more AP to get to the next level.
b) There was also the problem of catchup. If a player started Legion a few weeks or months after it launched, they might never be able to catch up even close to an appropriate artifact weapon power level — enough to raid or run instances with their friends who had been playing since the start, for example. Thus Blizz introduced Artifact Knowledge (AK) to allow players to accumulate AP at faster and ever-increasing rates. At first players had to unlock AK, but later Blizz just automatically applied it to everyone on a weekly basis for several weeks at a time. So, for example, the WQ that started out awarding maybe 300 AP would eventually award something like 100,000 AP.
c) As a result of these two mechanics, by the end of Legion players were earning obscene amounts of AP from each world quest or other AP source, in order to reach flabbergasting AP goals for the next artifact weapon trait. The numbers really did get ridiculously large.
2) In BFA, Blizz decided to use an opposite approach. That is, instead of increasing the amount of AP required for each successive AP goal, the amount of AP required for lower levels would decrease each week. This still allows for catch-up but avoids the humongous numbers of Legion. So, using made-up numbers for simplicity, if it took 1000 AP to reach level 12 in week 2, in week 3 it might take only 900 to reach level 12.
a) One fallout from this is that players can actually lose accumulated AP when the goal changes, in order to maintain the same percentage of progress towards the goal.
b) So using the same example, if at the end of week 2 a player had accumulated 500 AP towards the 1000-AP goal, when the number was decremented in week 3 suddenly the player might have only 450 AP, the number needed to maintain the 50% progress number.
Next, the gear controlled by the neck piece. Each player can equip three pieces of “Azerite gear”, dropped as loot from quests and raids and such. Note that this stuff drops very frequently, at varying ilevels, allowing players to pick which pieces they wish to equip, along with traits for specific situations (heavy AoE, heavy defensive, etc).
A. Each piece of gear has a series of traits, presented to the user as four concentric rings, each ring having 2-3 possible traits. A player unlocks these rings with specified AP levels. (There are several very good guides to Azerite traits — none of them, of course, by Blizz. Here is one from Wowhead.)
1) Lower ilevel Azerite gear requires lower levels of AP to unlock the rings. The higher the ilevel of the gear, the more AP it takes to unlock any of the rings. For example, a piece of 320 gear might require only AP level 15 to unlock the first ring, AP 17 to unlock the second, etc. But a piece of 355 gear would require maybe AP level 18 to unlock the first ring, more for subsequent rings.
2) Not all Azerite gear has all four categories of traits. Only high level gear has all four rings — most non-raid dropped gear has only 3 of the 4 rings available.
3) The total number of traits is not really known to anyone but Blizz, and it stands to reason they will keep adding traits for the duration of the expansion. There are at least dozens that are known now. Generally they provide either a class-specific advantage or a more generic one such as a defensive or role-appropriate one. In this way, Azerite gear is really only a continuation of Legion legendaries in a slightly different form.
4) Blizz has said the gear traits are not random. That is true only so far as it goes. That is, a player may see all the traits a piece of gear is imbued with and may select whichever of those traits seem best for each category. In that sense there is some player choice. But the range of traits available for any given piece of gear is random (or seems so) — two or three randomly-assigned traits for Ring 1, two or three for Ring 3, and so on.
a) Two otherwise identical pieces of gear could have two different sets of possible traits.
b) On the plus side, players do not need to equip the gear in order to see its traits or even to select the ones they want.
5) Players have the option to “reforge” their Azerite gear, but only within the confines of the traits the gear is already imbued with. If you think you selected the wrong Ring 1 trait, for example, you can change your selection, but only by selecting one of the other Ring 1 traits the gear came with. You cannot change the baseline set of RNG traits assigned to that piece of gear. There is a gold cost to reforging, and it increases with each reforge, but after a few days it resets to the lowest cost.
6) Even if higher ilevel gear has the same traits as lower level gear, the effect of those traits increases slightly, so in theory there is an advantage to replacing your lower level Azerite gear with higher stuff. The annoyance with doing so is that, whereas you may have had sufficient AP to unlock three categories of traits on the lower level stuff, when you replace it you may not be able to unlock more than one category.
B. I have not done any sims of Azerite traits, but my overall impression is that at most they might enhance your power by a couple of percentage points. There are a couple of OP traits still for some classes, but almost certainly Blizz will end up nerfing those.
The existence of this just surfaced in forums a couple of days ago, but seems to be a semi-stealth move by Blizz to change how they do the inevitable raid nerfs. As far as I can tell, it was never really announced — and it certainly was never hyped as a BFA “feature”.
A. It is apparently a replacement system to the one where raids become slightly nerfed across the board and game-wide after they have been around for a while and groups have gotten their world firsts and server firsts and whatnot.
B. It is a raid-only special buff to Azerite gear that empowers individual players and thus in effect eventually makes the raid seem nerfed. Here is the Blue Post “explaining” it.
C. The mechanics are that if you have a piece of Azerite gear with the Reorigination Array stealth trait (it will be listed in the trait tooltip for the piece), this trait is activated by killing three bosses in Uldir. The kills can be at any raid level, including LFR. After killing three bosses, you get one stack of RA whenever you are in Uldir, which buffs your highest secondary stat by 75. Each three bosses you subsequently kill adds another stack. However, you are limited to adding one stack per week, up to a max of 10 stacks.
Note that the ultimate effect of this mechanic — if indeed it is a replacement for across the board raid nerfs — is to make raids easier for those who already know how to kill the bosses. Yes, it does help such players to down bosses in higher level raids, but it seems to cut out those players and teams struggling to get through Uldir at all — no across the board nerfs for them. All nerfs, in other words, are the responsibility of individual players.