I am Alliance!! Through and through. 
However what I enjoyed about playing Horde is:
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Easier to build up a party for random content. Did all the BfA expansion raids as Horde on my DH despite starting in 8.2. Not so much on my Paladin.
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Genuine war mongers. I think it’s fair to see Horde as being assertive and dominant and Alliance as being reactive. Varian came off more as being assertive than our current king.
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Blood Elves: I do understand why people like them so much. They still have all their ‘high’ culture but are very clearly flawed too.
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I tried KV on both sides and the skill difference is huge.
Despite these, I do enjoy Alliance because of my guild. Though most of my real life friends who play are Horde.
Orcs cook the best bacon 
The adults.
I’m fine with Orcs being warlike and regulating themselves through combat. I just get the impression that if the Horde isn’t trying to conquer something they don’t seem to have a purpose.
Like what’s the value of conquering Stonetalon Mountains? It has been inhabited by Druids for millennia (Shu Halo and Kal Dorei) and I don’t see much in the what of resources there. And the Cenarion Circle is a threat to absolutely no one. Well except maybe Hemet…
… Garrosh’s orc supremacists?
Read the rest of my post please 
The horde appreciate the art of choppin’ down trees or anything else that gets in your way. They are a lot more supportive than the alliance when you get carried away into a lumberjack rage while clearing some trees out and happen to chop up a few elves or kul tiran in your blind lust for more lumber. How am I supposed to know the difference between a normal tree and a treant-form druid…“Stop! Don’t kill me!” is exactly what a tricksy tree would say to not be reduced to splinters!
1.) Orcs
2.) Non-generic and somewhat interesting story
3.) Previously had racial leaders that were cool
4.) Doesn’t have Tyrande, Malfurion or Illidan
I cringe every time Tyranda shows up. Is it sexist to say I liked her better when she stayed in the Temple of Elune and didn’t say anything? I swear watching her and Malfurion is like watching a bad imitation of a Mexican soap opera. “Shando?! Where’s my Shando?” 
1: We used to have balls, whereas the Alliance never did.
2: We matter in the story, whereas the Alliance never will.
3: Spikes.
Just saying, that term’s kinda in use already, and if it wasn’t it would be a no true scotsman. We’ve been pretty diabolical for 3 of the 8 expansions so far, and in a couple others we still behaved fairly dastardly. It’s best to accept the blood lust and the bouts of malice, it seems inseparable from the Horde’s identity at this point, and it’s not like the Alliance can do anything about it, no matter how much the players complain. They’re helpless.
Who knows? Maybe Baine’s council can calm stuff down, now that all the bad actors are finally booted out. Well, mostly, that one Vulpera woman whose name escapes me seems insanely aggressive and the Maghar leader seems pretty gung ho for killing some Draenei.
I’m attracted to the Horde because I really don’t want to be on the receiving end of its shenanigans.
The 3 expansions both have warmonger leaders, Cata and Mists were both Garrosh, and Legion and BFA Sylvannas, which were consequently the ones that mainly had that, now with the council the Horde can go back to being the Thrall’s Horde style again.
I don’t play Horde, but I’m guessing people like the races available. I play Alliance because Alliance has Dwarves. The only other thing is when I play my Horde toons, I realize how much nicer the Alliance’s stuff is, but other people might like that mud hut and tent aesthetic.
Vulpera. I’m Alliance through and through, mostly because of aesthetics, and because my friends are Alliance. If I had more friends Horde side, I’d play more.
Until the next warmonger starts stuff. Or maybe they throw a curve ball this time and the Alliance starts stuff and the Horde just goes with obscenely disproportionate retribution next time. Even Thrall’s horde still had the Wrathgate, which we now know was the Horde’s doing, albeit only Sylvanas’ faction of it, and the Broken Front.
It’s not that I don’t think Baine will be be peaceful, it’s that I think the Horde will utterly wreck the Alliance’s 
again despite him being peaceful, and there’s a good chance he’ll be out of power in 4 expansions, councilor or no; no Warchief’s tenure has lasted longer than 3 versions of the game.
There are currently 4 and a half unstable or only semi-stable characters: the Maghar leader, the Night Elf leaders, the Worgen leader, and a prominent Vulpera character.
Forget having skulls on your caps, if your cap is a skull, you’re almost definitely a baddie.
Yeah, I’ll choose Horde, better with the psychos than against them, I’m way less likely to get blown up this way.
I created Horde toons to understand both sides of the playing field. In some cases, they have some really amusing quests. Blizz does have a sense of humor.
Frankly it shows each other’s views from their own perspectives when you play both sides. You understand the struggle more when you play both.
It also tells me why war between the factions should come to an end.
Also… I like Vulpera.
Way better and more interesting races.
My girlfriend always called me an Alliance player with a Horde heart, I only played for the Worgen. But Tauren, Trolls, Vulpera, and Pandas all on the same faction is so cool. c:
WC3 to me shows Thrall and the Horde to be much more honorable and reasonable than the Alliance and Garithos.
Before someone mentions me being on an Alliance lock, I only made it and am leveling it to slaughter Vulpera in low level pvp.
There are more players on horde.