The only thing that stopped people from hating him in TBC was the fact that he was then considered a minor character.
Blizzard has been saying from the get-go that they had plans for characters like Garrosh and Saurfang the Younger right when they were introduced. Heck, the latter's quests even hint towards it because he says right out that he's going to go off and travel.
Garrosh's story was also kind of foretold in Nagrand as well, when the Mag'har Orcs being held captive by the Ogres claim that someone will rise up and lead the Mag'har to glory, or whatever.
This actually drove me nuts, since their plans made zero sense.
If Garrosh was destined for evil they could've skipped the TBC wimp phase, and given him a backstory that would actually make his descent into evil make sense, rather than a characterization rollercoaster. (Also, I don't remember that being said by most Mag'har draile, just that Geyah said Garrosh would be a great leader if he got it together)
And dranosh... he went off to travel... then suddenly he's in the Horde military? And we interact with him for all of two quests before he dies?
Blizzard has this annoying habit of killing kids to make the fathers get angsty and provide characterization to the old lame guy no one likes, rather than the fresh blood.
(We saw this in Gilneas, and heck, Anduin may not always have been intended to get healed)