So this leak was posted on scrolls of lore not too long ago and was immediately removed followed by users told not to talk about it or they will be banned, it was also posed on Reddit forums and the post was immediately removed.
Leak to follow
All of this is pre demon blood so no humans with the draenei being the main Alliance force. Garrosh goes back in time and stops his father from drinking the demons blood and Gul'dan is banished. He brings technology from the current time to reinforce the Horde. Ner'zhul uses this and rises to power once more to try and gain Garrosh's trust in the....Iron Horde. The Iron Horde forbids demon magic but it's pretty likely Gul'dan may end up summoning the Legion still even on his own. We get there via the Timewalkers.
I dunno how exactly Garrosh gets to the past yet. But his escape is explained in a upcoming short story with the start being his trial. Garrosh says he regrets nothing while laughing crazily but Anduin still believes he can be redeemed. Baine wants to personally execute Garrosh and Jaina is still her raging self. Eventually it comes to that scene we see in that Timeless Isle quest with Anduin talking to Garrosh. I dunno the rest of the story yet but it's likely Anduin and Zaela help Garrosh escape.
5.5 was to be 2 scenario's showing Garrosh's escape but since they are short on time 5.5 was scrapped for the above story with maybe parts ending up in 6.0. It was also to tie into the Timeless Isle.
The ORIGINAL story for the expansion was that Garrosh was banished to Outland but managed to get a artifact of Nozdormu. He used the artifact to summon the great heroes of the Horde and then 're makes' Draenor with the artifact pulling in new landmasses that just tears things up more. This was later scrapped for time travel.
The Alliance start in Shadowmoon and their capital is Karabor which is similar to Terokkar now. Karabor looks like how it does in the TBC trailer with Akama but brighter. The Horde starting zone is a new zone west of Blade's Edge in the Frost Wolf Homelands where their capital is a captured Ogre stronghold city. The zone itself is a tundra.
Netherstorm is Faralon but will be released in a future patch. Hellfire is a jungle where Garrosh is constructing the Dark Portal so he can invade Azeroth and 'make things right'. Zangar is a sea full of giant mushrooms. Shattrath is taken over by the Iron Horde and is a raid along with Auchindoun being a dungeon/raid. The other raids are The Blackrock Clan Citadel and a Ogre Stronghold. The first dungeon is in the Horde starting zone and is a Ogre Dungeon Cave where we rescue slaves.
The zone south of Terrokkar is the capital of the Arrakoa and is where their palace is located. It's like Terokkar but has a LOT more tree houses and flying Arrakoa. Maybe they end up doing something with their Old God.
There's some new tiger race as well but no details.
The Iron Horde has dominated the Gronn and uses them as giant siege mounts similar to the mammoths in LotR.
The 'Warlords' are all the chieftains of the old Horde with Durotan being the only good guy.
Some of the main heroes of the expansion are Velen (dunno if its Velen meeting himself or just past Velen), Maarad, Vol'jin, Thrall, Durotan, and some dwarf and tauren.
There's a continent southwest of Draenor which is the homeland of the Ogres.
Hope you enjoy reading