In their own words...

[OIS]

In a best friend rivals kind of way.

Could be. Anduin visited him in prison, even saved his life. That was after Garrosh made a your mom joke, that's friendship right there.

[Felfaadaern Darkterror]

Right, because every little thing in the game has been updated to fit the story.

It is what it is. Title of the thread is "In their own words" not "What they might say in an xpac that hasn't been finalized yet".

[SoulSoBreezy]

War Chief Sylvanas Windrunner:

• "I have no time for games."
• "We are the Forsaken. We will slaughter anyone who stands in our way."
• "What joy is there in this curse?"
• "What are we if not slaves to this torment?"

King Anduin Wrynn:

• "Greetings friend."
• "For the Alliance above all."
• "Be vigillant."
• "A just cause is always worth fighting for."

Yeah so hard to tell which sounds more like a mature, mentally stable, admirable leader who cares about all their subjects (not just their own sub-faction) and could inspire loyalty.

Four quotes don't define a faction leader. Use the book to fuel your narrative when it comes out =)

[Archibalde]

Lor'themar tells the player not to touch his hair, yet he proved to be a great leader and tactician during Mists of Pandaria... Lines when you click on the leader hardly means anything. It's a quick way to highlight their characters. Sylvanas is a tortured soul who desperately wants to survive because the torment of undeath is still better than what awaits her in the twisting nether. Of course her lines are going to be gloomy and edgy. Anduin on the other hand is a positive, cheerful person so his lines reflect that.

The story itself is what matters.

[Viconia]

Sylvanas's chatter was created for Frozen Throne, where she began as part of the Scourge, and was understandably bitter about everything. They re-recorded those lines for Wrath when her voice actor changed, at that point she was still mainly about taking revenge on Arthas. After that she felt she was done and committed suicide, but since there was literally Hell to pay, she decided to keep on living and pursue new goals. Therefore it's safe to say those lines are, in a manner of speaking, outdated as fuck.

Can't argue Anduin has a level head for his age, though.

[Evangeliste]

Sylvanas's chatter was created for Frozen Throne, where she began as part of the Scourge, and was understandably bitter about everything. They re-recorded those lines for Wrath when her voice actor changed, at that point she was still mainly about taking revenge on Arthas. After that she felt she was done and committed suicide, but since there was literally Hell to pay, she decided to keep on living and pursue new goals. Therefore it's safe to say those lines are, in a manner of speaking, outdated as fuck.

Can't argue Anduin has a level head for his age, though.

Well she didn't decide to live, she committed suicide. That's contradictory. Unless you are paraphrasing about the Val'kyr. I would agree though that she has been personally revived by the experience because of the damnation she felt. I doubt she'd have tried suicide if she knew what lurked on the other side and why she went to Helya afterwards.

I wouldn't say they are all out-dated, 2 are well deserving for now. She can still be cursed, mentally and tormented by her affliction of undead as the Forsaken - it's why she went to Helya and tried to do whatever to Eyir. If anything she is even more tormented as Vol'jin has effectively trapped and enslaved her to a role where her freedom is severely restricted, huge amounts of responsibility and pressure with still no solution a massive plight with procreation and keeping her herself away from the Shadowlands that now has been active from Wrath [for her soul] and Cataclysm [for lesser amounts of Val'kyr] when Godfrey betrayed her.

And really has no time anymore as Warchief.

The Forsaken is narrowed down but we really have no proper feel [yet mind you] that she is all for the Horde, the Battle for Azeroth trailer was in Lordaeron. Her home. Her seat of power. Thrall was in Orgrimmar that houses several races, even dedicated zones to races. Undercity and Lordaeron is basically all Forsaken.
I would be more inclined if it was Highmountain or Orgrimmar but those factions will be beckoned and come to Lordaeron as she is their Warchief. Even Sylvanas answered the call, when her Warchief Garrosh wanted her to sack Gilneas. I get the point Anduin and co want Lordaeron as it was Human but it still doesn't bode well from previous observations of Warchief demands [like Sylvanas and Garrosh] it needs to be answered regardless of will or not. And Sylvanas didn't seem very 'For the Horde' by running off to Stormheim for clearly a personal agenda, most rulers would reside back and preside over their kingdoms.
On most occasions, other faction leaders like Varian, Thrall, Vol'jin and at times Garrosh have done that. Anduin too has done that, remained in his seat of power and potentially worked his shit, that can be seen when he walks the streets of Stormwind at least. He's engaging and understanding his populates. Of course, Greymane needs to be restrained but Anduin did what most rulers do, send subordinates, obviously the Sky Captain sided with Greymane and a direct attack on Sylvanas but that wasn't Anduin's choice, they deliberately interpreted his order how they chose by being offensive than defensive as suggested. Sylvanas on the other hand, went personally despite her utmost importance now to several races, there's only really a few choices for faction leader left and not sure how they'd fair either. If Anduin went, there's plenty of stronger choices than Horde to go by like Jaina, Velen, Greymane perhaps Tyrande but with the burning of Teldrassil, would be a better premise.

[Felixon]

All of this bickering on forums about the faction war is pointless.It's a question about the persons morality.For some,the way the Horde deals with problems is fine,for others,it's considered as a war crime and genocide.

[Aeula]

I agree, Anduin is a complete dick.