Originally Posted by
Wikiy
You have it all wrong. Garrosh was never meant as a villain in this expansion, just a catalyst, a gear in the story. It still surprises me how many people were surprised by his death. I suspected they would get rid of him from the very start, and not disappointingly, they did. At Blizzcon, the devs said (and they didn't seem to be joking) that the final boss would be Grommash Hellscream. Furthermore, during Tier 1, we get rid of only two warlords, Blackhand and Ner'zul, and I'm not even sure if counting Ner'zul in as a warlord makes any sense since Gul'dan is even now pretty much more powerful than he is, and they're both members of the same clan, meaning Gul'dan is probably the one to consider a warlord. Regardless, there's still Kargath, Kilrogg and Grommash left.
Also, the Burning Legion never had any plans to invade Draenor. It's the one planet where they realized invading would make the Draenai flee with the help of Naaru again, accomplishing nothing. While they might have changed the Burning Legion's decision in this timeline, I'm still very dubious about the idea that this is going to be a Burning Legion expansion. While I love the Burning Legion theme, that would be outright deceiving the players.
Personally, I only really expect the Burning Legion in this expansion as a part of a content patch with a Gul'dan raid, where he's trying to summon either Mannaroth (to make the orcs drink the blood again, but I'm doubting this since Blizz said Garrosh already stopped them from drinking the blood, but tbh even the devs themselves don't have half a clue what they're doing to the story right now) or, more likely, Kil'Jaeden.