World quests are arguably Legion's biggest addition. They're essentially Diablo III's adventure mode, polished up and ported to World of Warcraft to serve as infinite content to players. Your map will be constantly filled with points of interest, from world bosses to particularly active fishing pools, letting you know where things need doing.
Special loot will be given out for doing a certain number each day, and particularly rare ones will give particularly great loot. They'll also hang around for a lot longer, so if you can't log on every day, you'll have a stack of them to do when you do.
This is all thanks to scaled zones, which allow all of the Broken Isles to operate as one massive endgame area. This, along with raids and Mythic+ dungeons will be the meat of life at level 110.
The game's sexiest new class, rippling pecs and tattoos and all. Simply, they're a mixture of a Rogue and a Warlock, slicing enemies to pieces with signature warglaives while using dark magic to protect themselves, deal damage and hurt people. They also have a tanking spec, Vegeance, which sacrifices signature mobility for damage absorbtion.
Rather than give you the full spec of the Illidari down here, here's where you can learn more:
On the PvP side of things, Blizzard are completely overhauling Honor. It¡¯s not about gear anymore; it¡¯s about PvP talents. This is a new progression system specific to PvP, which allows players to work their way up through the ranks, unlocking new talents, just like in PvE.
The new system will start with 50 ranks, but once you reach the cap, you can start all over again, sacrificing your rank for cosmetic rewards like new mounts and PvP artifact variants.
While the importance of gear will be greatly diminished, it will impact your effectiveness in PvP by a tiny amount. Talents will be the majority of your power bump over newer players, however, and Blizzard have already begun rebalancing classes specifically in PvP by altering their base stats.
Professions on the Broken Isles are getting a bit of a facelift. Crafting is much as it ever was, grabbing reagents to make items and letting you get a little ahead of the game. However, acquiring new recipes now involves in-depth quests specific to that profession, giving more of a discovery feel, while reagents are harder to get due to Blood of Sargaras - the rare, vital crafting material used in every profession - being Bind on Pickup. You'll have to gether it yourself.
Professions, and everything else involved in getting ready to raid, are covered in more detail in our World of Warcraft: Legion gear guide.
Flying in Legion has been a massively contentious issue. After much back and forth between Blizzard and the community, it will be unlocked via an achievement at level 110, the first part of which is already in the game. Broken Isles Pathfinder, Part One requires you to explore the continent, finish the major quests, have every faction be happy with you, complete 100 World Quests and finish your Order Hall campaign. This lets your mount go faster, but won't yet let you fly.
In a future patch - which should be sooner than Warlords of Draenors 6.2 - this will be needed to unlock flying. Exactly how that will work hasn't yet been revealed.