Love it how Horde players always seperate the "Old Horde" (Warcraft 1+2) and the "new Horde".
Yet "Alliance of Lorderaen" and "The Alliance" get grouped together when talking about faction heroes gone bad.
Arthas - Alliance of Lorderaen. Not the alliance we know
Kel'thuzad - Alliance of Lorderaen, left Kirin Tor and became the Lich Kings (Ner'zhul - OLD Horde) servant.
Illidan - non, since Night Elves weren't part of the Alliance then. And they also weren't part of the Alliance when Malfurion BANISHED Illidan from Kalimdor
Kael'thas - Was about to be executed by the Garithos and the remains of the Alliance of Lorderaen. Kirin Tor not lifting a finger. He only helped the alliance cause of old debts between High Elves & Stromgarde.
Also, how is Wrath an Alliance expansion?
Sure Arthas who belonged to a different Alliance than the current one was the LK (after mindstabbing Ner'zhul in his mind in the novel), but most of the scourge was created when Ner'zhul was LK. Not to mention that the major factions going after the LK were 2 NEUTRAL organizations. The Argent Crusade and the Knights of the Ebon Blade. Alliance & Horde only going there cause the LK assaulted the Alliance and Horde capital city.
Questing wise there was nothing about alliance dominance. Think the only anti-horde quests in the game were Battle for the Undercity and the quest in Howling Fjord where we destroy some Forsaken plague machines.
Wrath was both factions with the help of 2 neutral organizations dealing with the LK.
Cata was Horde takes over many contested zones (to balance leveling zones out), Thrall marriage, Old Gods/Deathwing and ending the xpack with Theramore.
Alliance had hardly any development. Worgen get shunned away to Darnassus to 1 tree, 1 3-house base in Blasted Lands with 2-3 npcs and 1-2 quests. Goblins get formerly "contested" Aszhara with Bilgewater Harbor as a city (not capital) to play around in when leveling.
Maybe if we a named alliance NPC confronted Benedictus instead of Thrall and Worgen getting some development after their starting zone like the goblins, it would be somewhat more fair.
MoP. 5.0 was somewhat neutral. 5.1 is almost 50/50 alliance/horde wise (although Dagger in the Dark was imo the superior faction scenario)
5.2 is 50/50 again with the "debatable" alliance fist pumping that is known as The Purge of Dalaran.
5.3 was better developed for the Horde, Alliance got shafted.
5.4 seems thus far to be hordecentric, with MAYBE alliance development of the SoO aftermath in 5.5