"Do not repeat the mistakes of your father"
"Your father dabbled in powers he did no understand, where is he now?"
I didn't play WC3 but I am a lorehead and as a Warrior main Grom Hellscream is probably my favorite character. I mean the guy one shots Mannoroth in two separate timelines, Illidian couldn't even take him down in a duel, and Garrosh couldn't even one shot Taran Zhu with the same weapon.
Yet he's given this duel identity of Savior and Betrayer. I find that far too harsh, Grom was a hot headed Orc no doubt especially in his younger days before WC3 but he was nothing like Garrosh. He was the first to drink the blood of Mannoroth yes, but I'm pretty sure that had he known it was the blood of a 50 foot, interdimensional, space demon, he would have thought it was a bad idea. You notice in the cinematic Mannoroth doesn't appear until he rejects the blood. So yea trusting Gul'dan was bad idea that pretty much damned his people but he didn't know any better. Once again he was stubborn and hot headed but not a total warmongering buffoon like Garrosh.
He drinks the blood yet again on another occasion, I believe this time he knew about the dire effects it would have. However in this case it was either drink the blood...or get torn to shreds by the xenophobic Cenarius who wasn't up for negotiations. He made a dire judgement call, he didn't want to see his clansmen slaughtered. Then as we all know he later redeems himself for this action very quickly in a blaze of glory.
So now we have Garrosh....someone who I feel is thee worst developed character I have ever seen. He starts off wimpy in TBC fearing he'll repeat his father's mistakes (which he blindly does eventually). Thrall shows him what a hero Grom was and BLAM. Thrall inadvertently creates a monster, this guy is now a warhungry hardheaded idiot that wants to fight anything that isn't Horde. He instantly makes a ruckus at the Alliance peace summit getting into it with King Varian.
Now Varian is a very interesting character who we start seeing develop in WoTLK. We are first introduced to him as Horde during the Battle for the Undercity, here he wants to here nothing of Thrall's explanations for the atrocities at the Wrathgate and simply wants them all gone. At first I thought he was a total prick but Varian unlike Garrosh though has every reason to despise the Horde. His father was murdered by an Orc he trusted (Garona) his city Stormwind was quickly razed afterwards and finally his adoptive father Anduin Lothar is killed in combat by the Orc Warchief Doomhammer. I mean talk about childhood trauma. Yet Varian is still more reasonable then Garrosh when it comes to dealing with the Horde, mainly due to his son. Let's not forget that Varian's psyche is still a little unstable ever since Onyxia split his warrior side from his diplomatic side, as of now he's still more Lo'gash then King Varian.
So Garrosh has no reason to hate everybody, but he does. He was all for a war against the Alliance and the Scourge during the campaign in Northrend, some of his officers even making the Alliance a priority. Thrall then thinks it's a good idea to put a young orc whose only been a part of the Horde for two freakin years in charge of the Horde as the new Warchief. -_-
The only explanation I can think of for his personality is that Garrosh is a Draenor orc, a hotheaded one at that with daddy issues, having not experienced the atrocities of the demon bound Horde he hasn't learned any humility.
So now WoD is apparently featuring Grom as the final villain....like why? We hated Garrosh, his very existence was an insult to Grom's legacy after his redemption...and now he's the bad guy? Like WTH, why does Blizzard hate this guy so much?