Is there any reasoning why do they join Garrosh? I mean in the original story orcs were convinced that drenai are going to attack them and all. Are they doing it in exchange from Gary's tech? Orc and Drenai wasn't hostile against each other, respected each other and rather stayed of each other ways.
Why do they want to invade Azeroth? They got tech from Gary now and as we know Drenor is mostly savage and unoccupied so why do they need azeroth?
It's like: "Hey this dude give us tech we don't need, let's kill innocent drenai and go to the world we don't realy care and mayby die in our way!"