Its the same person who leaks Warlords of Draenor and Legion before announce.
Consider this less than a grain of salt.
Saltypigeon (same guy who leaked the plot/ and talents of MoP and WoD prior to their release) posted a short descriptive list of what to expect from specs in Legion on MMOChampion
I can't find the post anymore as it was possibly deleted by the moderators or himself (just like his previous posts) but luckily i copied and pasted it before sending it to a FB friend.
Choose to believe or not to believe, criticism is welcome. I'm just copy/posting it here cuz it sounds cool and all. Formatting will make it hard to read as it's copy and pasted
coo coo, saltypigeon here its that time of the month again peeps, I'll only post a bit of what i know, no im not listing every single class, only gonna be giving a fraction of me love to those that weren't given any in the announcement trailer
WARRIORS
BLADEMASTER (Arms) New resource bar "Precision Bar"
Rage bar is not removed in place for this
Strike from Cata returns as a builder for precision
The fuller the precision bar is the more times you could use Overpower
Abilities that cost rage builds up Precision
-Bloodied Axe of Cenarius
BERSERKER( Fury) Fast paced
Haste reliant
Low Global cooldown (good luck with carpal tunnel)
(SPOILER - Varian goes out in a similar way as Brox, being the 2nd mortal to strike Sargeras, Fury warrior's pick up his separated Shalamayne, 1h Fury wield Ellemayne and Shala'tor, 2h fury wields Ellemayne and Shala'tor combined with the broken pieces of the Great Sword of Stormwind recovered from Blackrock Mountains)
GLADIATOR (Protection) gladiator stance is now a passive with minor adjustments the vrykul artifact weapons give prot some juicy bonuses MONK
WINDWALKER
Brews are renamed and no longer brews in order to fit class, the abilities remain the same however.
playstyle/lore (TEB = Chi Efflux, Energizing Brew = Xuen's Orison)
Crackling Jade Lightning is now Crackling Jolt - Burst like ability similar to the current Siegebreaker
Artifact weapon customization will change the color of your visuals (Teal green, Orange, Yellow, Blue)
BREWMASTERS
Stagger Removed, New more appealing system taking it's place
Artifact weapon is a keg that shows on your back, when sheathing; mugs of beer are wielded in your hands.
MISTWEAVER
lots of complaints incoming for mistweaver monks, sorry
Less mobile - More casting
ROGUES
Generally are less cooldown reliant in legion
COMBAT
removing insights
Main Gauche is redone (1 parry = 2 gauche strikes)
pirate-like gameplay style with the use of mid range gun execution, lots of parrying
SUB
sub rogues will be getting an ability where they untarget themselves without vanishing/stealth, unlike vanish, this does not exit them out of target, instead, it acts as a really short stun
Valeera Sanguinar's Daggers but not really
ASSASSINATION
DoT reliant, heavy procs with each dot
No big changes
No clue about Artifact wep