So, after this week's Expansion leak I've been contacted by a few reliable sources, and this is what they have to say about 'Rise of the Naga Empire':
•They claim that the recently leaked email was part of a chain of emails discusing the Expansion's development and the features to be included.
•In the series of emails, we can see the final name of the expansion isn't decided yet, and that 'Rise of the Naga Empire' is just one of the few proposed ones, acting as a placeholder for now. It seems they can't find a name which properly defines the bases of the expansion and its plot.
•The plot seems to be pretty much the same through the emails, pointing to the Naga invasion as beign the pre-expansion event, with them attacking Orgrimmar and Stormwind through their ports, and many other places around the coast. This invasion will resemble the Legion and WotLK's ones.
•Also, the ritual described in the past leak is supposed to raise naga zones/cities to the surface, as a method of avoiding the naga part of the expansion to be centered only around underwater zones, thus making Nazjatar and its surroundings a non-underwater zone like the Broken Isles, specially Suramar.
•The Naga are still very strong candidates for becoming the next playable race, but the problem the team is facing is still the same. Their models and animations wouldn't match some of the standard animations like the monk ones, but they're working on some alternatives for them. Also, some of them feel like the problem with pants and boots shouldn't be that important, since Trolls, Tauren, Draenei and Undead already have diferent ways to wear them, but they also say it would be a lot of work for them to make their models 'feel right' to play with.
•The possibility of a racial ability which allows them to transform into Night Elves (as seen a few times in-game) has been discussed, but most of them think it could be problematic for the Horde ones.
•Wether they would be a neutral race or not is still in discussion, and the main reason for this is the posibility of Illidan's Naga joining the Horde, and the Broken joining the Alliance. Most of them think that a new Broken model would be too much work and not worth the effort, and feel more comfortable with the neutral race idea.
•They also point out that from lore's perspective, a few naga deserting and joining either their Night or Blood Elf descendants feels easier to explain and fit in the Expansion's plot than making Illidan's Naga, an elite force, also join their former allies (the Blood Elves), but starting at Lvl 1 after Legion.
•The classes aviable for the playable Naga race would be Warrior, Rogue, Hunter, Priest, Mage, Shaman and maybe Warlock. The team doesn't want them to have less than 7 clases aviable for balance reasons.
•The other two races beign considered to become playable are High Elves and Forest Trolls. They feel relevant to the story, but the team fears the players could see them as redundant because of the Blood Elves and the Darkspear Trolls.
•Playable High Elf classes would be Warrior, Rogue, Hunter, Priest, Paladin, Mage, Warlock, DeathKnight, and Monk.
•Playable Forest Troll classes would be Warrior, Rogue, Hunter, Priest, Mage, Shaman, DeathKnight, and maybe Warlock, Druid or Monk.
•Adding the High Elves to the Alliance could solve the sugested Naga racial's balance problem, and making High Elves playable for the Alliance and Naga for the Horde has also been discussed.
•The Tinker class is indeed beign discussed, but not decided yet to be added in the Expansion. The main reason for this is the lack of context for it to be relevant in the story they're trying to tell. The one presented to us in the last leaked email seems to be just one of the proposed.
•It's specs are also intended to be Tank and DPS, but a third Ranged DPS spec is also discussed. Most of the developers involved think that it could be 'excesive' and maybe too similar to the Hunter class, leaving an Hybrid spec like Paladin's Retribution as a better option for the Tinker class. It also seems the team doesn't feel confident on adding another 2-spec class in the game right now.
•Night Elf and Undead Paladins are supposed to be added in a patch, and not as an Expansion feature. Other considered candidates for new race/class combinations are Worgen Paladins, Draenei Warlocks, Goblin Monks, and possibly but not likely Gnome Paladins, Blood Elf Druids and Orc Priests. The discussion about the Orc Priests was mostly about Shadow Priests. Tauren and Draenei Rogues are still beign discussed, specially because of the Rangari, but not confirmed yet.
•Kezan will be the first questing zone for Horde players. They will find it mostly in ruins and abandoned after the Cataclysm. Horde players will have to fight through the Isle and reconquer Undermine, making it their main city for the expansion.
•Undermine was also heavily considered to be the main neutral city, as seen in the last leaked email, but it was difficult for the team to think of another unused iconic Horde location to serve as theirs.
•Kul Tiras' peninsula will be the same but for Alliance players, beign Boralus their main city. Alliance players will also find the zone heavily damaged, and will have to defend the isles against a Naga assault, securing them once more for the Alliance.
•It is said that Jaina Proudmoore will most likely be the new leader of Kul Tiras, but the posibility of bringing Tandred Proudmoore to canon is also pointed out, though not well recived.
•Since Kul Tiras is formed by different islands, other zones are mentioned to be possible parts of the Horde's questing experience, such as the Lost Isles or the resurfaced Darkspear Islands, where we could meet one of Vol'Jin's sons as part of the quest chain, who would eventually take the mantle as leader of the Darkspear.
•Tanaris will have a new phase, like Theramore and Blasted Lands, featuring a Hearthstone-like Gazgetan, making it the main Neutral City for the expansion and the Capital of the Steamwheedle Cartel, since Undermine is now part of the Horde.
•It's beign discussed what would happen to the players hated by the Steamwheedle Cartel, and while some of the developers are thinking of making the new Gazgetan phase neutral to them anyways (thus ending also the posibility of players killing the city's NPCs), some of them are sugesting to let those players go to Plunder Isle, since Gazgetan isn't going to be a focal point of the Expansion unlike Dalaran in Legion.
•Kul Tiras and Kezan will allow the players to travel to the leveling zones and their Capitals (Stormwind, Orgrimmar, and Gazgetan/Plunder Isle), and will have a Shipyard like the one on WoD's Garrisons, where the players will command their faction's navy and send them to quests. The Shipyard and the main city will also have a campaign like the Legion's Class Hall ones.
•Boats will indeed be part of the mount sistem, and the toy ones will be moved into mounts, but they will not be part of the core experience of the Expansion. They're just for fun and for fast travel in water zones.
•But, it was indeed intended to include a quest chain similar to the Thousand Needles' one, where you would have to use your own ship to move around, this time to take part in a naval conflict between the Alliance and the Horde. Wether if this would be or not included is still unclear, but it looks like it could be part of the Shipyard/main city campaign.
•The Faction Allegiance System is also one of the proposed ideas for letting people play with players of the opposite faction. It's not intended to be an Expansion centered feature, but an overall game one. The idea still lacks serious developement, as the team would have to face some difficulties, like allowing cross-faction comunication using common and orcish, or giving the common language to all horde races instead of orcish, and the fact that some dungeons, raids and events are faction-designed.
•Zandalar is intended to be the main protagonist zone for the first major patch, which will have a 'Rise of the Thunder King' vibe to it, changing some NPCs and some of Zandalar's sub-zones. It will feature an 'all out' attack from the Zandalari Empire to get rid of the invaders, and Hakkar is mentioned to possibly pop up in the patch.
•N'zoth would be the boss of the second major patch, and its plot will heavily resemble the 'Secrets of Ulduar' patch, this time with Jaina acting as Varian, and Khadgar as Rhonin. Horde and Alliance will be battling each other once again, while the Old God gains more power, and the Heroes will be forced to face him.
•Azshara will be the final boss of the Expansion in the third and final major patch, now weakened without the full power of N'Zoth to help her and her armies.
•Other minor patch ideas include the Ominous Island from 'The Well of Eternity' novel, and a possible patch before or after the Zandalar's one, featuring the reconstruction of Kul Tiras and Kezan, maybe as a final reward for their campaigns.
•One of the first raids aviable will be Abyssal Maw. The players will be sent there by Neptulon, who seeks revenge against Ozumat and the Naga, and will also explain how he escaped from there in the first place.
•Gishan Caverns are supposed to be an Instance, but not clear yet if a Dungeon or a Raid.
•The two revamped Dungeons will be Blackfathom Deeps, which will feature updated and more poweful Naga and Old God servants, and Zul'Farrak, which will be a new base for the Zandalari Empire in Kalimdor, far from the eyes of the Alliance and the Horde.
•Zandalar's patch will also feature a Max Lvl dungeon in the Temple of Atal'Hakar (Aka Sunken Temple), and will use most of the unused parts from the old dungeon. Hakar may make its mentioned appearance here.
•Dalaran might show up in the Expansion just like during MoP, but not as a major or relevant city for the Expansion.
•The conversations from the emails also point to the next Expansion after this one beign another world revamp like Cataclysm, this time including Northrend, and centered around the Black Empire. An actual Azjol'Nerub zone is mentioned, and also an Azjol'Nerub raid, but those might be different ideas for the same thing.
•Also, no plans for an Outland revamp yet.