Quite possibly the greatest source of information in regards to leveling I have seen for a new expansion. Bravo. Me and my friend are having a week long lan party at my house so we plan on leveling our mains to 120, doing all the week 1 shit and then starting at least another toon to get 120 as an alt (I personally am an altoholic, its bad, send help)
The community was apparently frustrated with Blizzard for a lack of communication concerning the issue, but it looks like that was due to the fact that their heads were down as they worked to understand the problem. It was explained that they didn't want to just roll out a quick bandage, as that would likely cause unforeseen issues down the road. Instead, they're crunching the numbers and digging into the code in the hopes of discovering a legitimate source of the problem.
In my opinion, Zygor makes the best WoW leveling guides. They have been around for more than 10 years, which shows their commitment to maintaining and updating their guides to provide you with an optimized leveling path for any class and race, whether it’s Horde or Alliance. Zygor is an addon that includes a waypoint arrow and a separate window with instructions that, taken together, show you step-by-step how to level your character to 120, FAST. You’ll know exactly what to do at all times. It’s also very easy to jump in at any level; you don’t have to start exactly at level 1 or 110 or anything. It’s a bit more expensive than the other options, but I’d say it’s definitely worth it.
It's not an enchantment, but you should buy or craft an iLVL 100+ belt, gloves, or boots with a gem socket for use with the new 5% bonus experience gem: Insightful Rubellite. I used a vendor-bought belt from the legacy valor vendor in Orgrimmar, since it was convenient and met the minimum ilvl bonus. Keep these in your bags until you can equip them, which should be just in time for treasure collections in WoD content. I didn't ever replace the belt until I dinged 110, since I didn't feel the stats from later upgraded belt drops made enough of a difference to outweigh the 5% bonus. This is explained below, in the WoD treasure section.
Pick druid, paladin or monk. Get heirlooms if you can. Grind mobs until level 5 - 6. Start doing the easy "just kill these mobs outside town" quests until 15. Queue rdf as every role and do every dungeon you can (with heirlooms you could probably solo the dungeons) while you travel to higher lever zones. Keep doing the simplest quests while you're waiting for rdf (which shouldn't be long). I leveled a druid to 100 once doing this in maybe a day /played, but he was also rested for most of the process.
En ce qui concerne la pièce d'armure contenant les améliorations d'Azerite, nous vous recommandons de prendre le Torse de Magni en premier. Si vous choisissez de commencer par Vol'dun, la première pièce que vous pourrez trouver sera un Casque, tandis que la dernière pièce seront des Épaulières. Cela vous donnera donc 3 pièces d'armure d'Azerite en quittant la première zone, ce qui vous sera d'une certaine aide.
Auto looting a mob will increase leveling speed for the expansion. to enable it = Esc, Interface, Controls, Enable Auto Loot. I'm including this because sometimes the simple things are missed. I, sadly, went 3/4 of the way through WoD not knowing that hitting the space bar for my mission tables is much MUCH faster than waiting it out. (i never claimed to be smart OKAY) =P

“Dugi’s guides are the greatest thing that has happened to me in my whole time playing WoW. I have almost all of them now and they are so helpful and easy to use. It couldn’t be simpler to install them and start using them straight away. The waypoint arrows are spot on and each step of every guide is detailed with everything you need to know. They really are perfect and i have recommended them to all of my friends in-game.

Résumé des informations (TL;DR) : Spoil Terminez toutes les quêtes disponibles, récupérez un maximum de Puissance d'Azerite, faites le Front de Guerre une fois niveau 120 pour récupérer un loot 370 ilvl et accéder aux quêtes, faites le Front de Guerre chaque semaine pour la réputation et l'AP, faites les World Quests pour la Rep/AP/Émisaires, trouvez de l'équipement grâce aux donjons et assurez vous de faire les 9 disponibles en difficulté mythique.
A: Buying gold from third-party services negatively impacts the game experience for everyone. The overwhelming majority of the gold these services provide comes from stolen player accounts, halting the victims’ ability to play the game and contribute to their guilds. On top of this, gold selling companies often farm resources using hack programs, sell fake product codes as a scam, and spam entire realms with ads to buy gold, disrupting the game in very real ways.

As always, I will monitor and update this guide as new information comes in. If I've gotten anything glaringly and completely wrong, just tell me with as much data as possible. The idea is to find the fastest possible leveling method, NOT to argue about how good or bad individuals are. If you have hard data, post it! If you have an idea, let the thread know so we can test it!
Fifth: As for Azerite Armor, I recommend getting the Chest first from Magini and if you do Vol'dun first, the first piece you can get will be a Head and the final piece from the zone with be Shoulders. That will give you all 3 pieces of Azerite Armor when you leave the first zone which will help out. If you are leveling a different spec from what you plan on playing, (i.e leveling as a dps when you plan to heal/tank) you will receive at least 2 pieces from every zone then 1 piece from starting the War Campaign that you can choose your Main Spec trait for. Pick the traits that will help you level the fastest.
Skinning is a good money maker as throughout your travels you will fight many beasts. It also won't take much time, only 1-5 seconds after every beast. Miners and herbalists have to travel all the way to the nodes. Skinning also provides the passive bonus Master of Anatomy, increasing critical strike (which is especially helpful for agility-based characters who take it with Leatherworking).
“We would prefer a targeted solution versus just applying a band-aid fix that could mask deeper issues that could cause problems down the line, but at some point it’s not fair to give you a degraded experience for the sake of that investigation, so we’ll likely go ahead with a blanket health reduction in the near future while we continue to investigate. Either way, the current state is not the game experience we intended, and it’s something we will fix.”
Quite possibly the greatest source of information in regards to leveling I have seen for a new expansion. Bravo. Me and my friend are having a week long lan party at my house so we plan on leveling our mains to 120, doing all the week 1 shit and then starting at least another toon to get 120 as an alt (I personally am an altoholic, its bad, send help)
If you want to spend as little time on your alt as possible - just do Legion Invasions. You can use sites like (https://wow.gameinfo.io/invasions) to track when the next invasion will be. Log in, fly to the closest world quest, and once there - right-click on the quest's name in your quest log and "Find Group". Sign up for some group, or if there's none - just start your own immediately, and people will come to you. It is 10 times faster to do invasion quests in a group. Once that particular quest is complete - leave the group, and fly to the next one, where you should find another group. Don't expect the group from one world quest to follow you to the next. Then you simply log out until next invasion. You can do 1-2 invasions a day, and each invasion will give you about a level or 1.5 of experience, if you have full heirloom gear. Each invasion will take about 20 minutes.
Fully rested experience (this is the blue color your experience bar takes instead of purple) grants 200% more experience per kill. Quest experience does not work the same as mob experience. Instead of just using the rested bonus, quest experience pushes the bar further upwards extending the rested bonus. Say if half your experience bar is blue. If you turn in 10 quests all at one the normal experience from them all could boost a character a full level. Unlike mobs where the experience gain will use up said bonus - the quests merely 'push' the bar further. Doing this could net you a level and still have the 200% bonus for mob kills applying to milk the rest bonus.
First: Azeroth Auto Pilot is a fantastic addon for those who just want to get the leveling done and have 0 desire to read text and watch cutscenes. I have submitted a lot of feedback to the developer over the course of its creation and after doing a play through on both Horde and Alliance I can strongly recommend this addon. For those who want to watch cutscenes, I am somewhat positive that there is an option to not skip cutscenes. I strongly recommend trying this out once BFA launches because even if you don’t skip the cutscenes the proper pathing and skipping of quest text will save you a lot time. I would like to note that the only zone where I encountered an issue was in Vol’dun where the pathing seemed a little off from what would make logical sense, but I have submitted that feedback to the dev and hopefully he has corrected it. THIS ADDON IS COMPLETELY OPTIONAL AND IF YOU DON’T WANT TO USE IT YOU DON’T HAVE TO. IM JUST GIVING PEOPLE INFORMATION FOR THOSE WHO LEVEL ALTS/HAVE PLAYED THROUGH THE STORY BEFORE/OR JUST WANT TO GET LEVELING DONE ASAP.

These two expansions are virtually identical in terms of exp/h. I personally favor Mount Hyjal, and think it's very slightly faster. But if you know Jade Forest well you can just as easily keep up there. Ultimately you'll end up doing both anyway, so it's mostly academic. Every time I've tested Valley of Four Winds or Deepholme, or any other zone in MOP/CATA's level range, they were worse exp/h. You should not even need to complete both zones to ding 91, so it's more important to just pick one and go. 

Something to keep in mind as well is that this will make enchanting materials more valuable, since it is likely most players will now simply scrap their boe greens instead of getting them disenchanted. Also redundant dungeon/raid gear can be scrapped rather than traded to the (guild) enchanter in the run. Less stuff gets disenchanted, meaning there will be less ecnhanting materials, meaning their value will rise. All the more reason to DE rather than scrap as an ecnhanter.