Thrall: went from someone absolutely dedicated to redeeming his people, the Orcs, and having the Horde become a positive force in the world it once sought to conquer. His shamanism was emblematic of his dedication to his people, their nation, and the honor and spiritualism of the Horde. He was born a slave but was taught strategy, diplomacy, and politics first by his master and then by his Orc mentors.
Then he was transformed into “Green Jesus.” He made the colossally stupid, idiotic, and asinine decision to make Garrosh Warchief despite all the obvious signs that he was a warmongering psychopath obsessed with carnage and conquest. Not satisfied with turning him into an idiot, Blizzard then forced him to abandon his faction and his people entirely in order to become the Elemental Savior of all Azeroth. Now he is a depressed, sad, tired, hypocritical loser who has to be FORCED to come aid his people by an Old Man, when originally the well-being of his people was CORE to everything Thrall was as a character. He literally crossed oceans to give the Horde a better chance at an honest life.
Jaina: The inquisitive young mage who once defied the hatreds of the past to not only unite with hated enemies to save the world, but also to recognize that a change was happening to said peoples and that persecuting them was wrong. Now her racist father has been vindicated by the convoluted plot, showing that no, the green men will never change, and yes Jaina was an idiot to trust them. She was forced to undergo a complete character 180 becoming an edgy, emotional wreck that rightfully hates the Horde. To compound this trainwreck, recently Blizzard has done another turnabout with the character, so even they can’t make up their bloody minds. Jaina, much like the lore, is now a complete mess.
I could go on, but the faults with others such as Sylvanas, Tyrande, etc have been well documented many times over. It is actually impressive that Blizzard has made me utterly despise characters I once cherished.
And it’s not just the classics. Everyone else they touch turns to garbage. Saurfang went from wishing to uphold honor at any cost, ready to strike down any threat to the Horde from within and without, to dragging his heels and having to be convinced by Manduin that he should grow a pair and face the Cartoon Villain Warchief of the expansion. Even someone like Magni, who forged the Ashbringer using the rage and grief of his brother’s apparent death, who was once the most senior member of the Alliance in the Eastern Kingdoms and ordered the Stormpike into AV under his Imperial Imperative has been reduced to fantasy Captain Planet, with no other personality outside of bemoaning how mother Azeroth is hurt.
I liken this to a really bad run of a iconic comic book. You want to love the characters that are dear to you, but you grow to hate them as bad writers make them increasingly more garbage.