Originally Posted by
earthwarden
I know he was aligned with Kil'jaeden since before, but there's a difference between scheming and open rebellion. And said open rebellion doesn't end up happening, what happens instead Akama tells Illidan of Kael's scheme, Illidan sends Akama's broken - actually the player in disguise - to send Kael his horse's head as a warning. All the way up until then - until the Hyjal attunement chain - Kael officially works for Illidan. The attack on Shattrath is way, way before that.
Attack on Shattrath doesn't seem like something that could happen without Illidan's knowledge or consent when Kael was still playing the role of the good lieutanant, and if it was, Illidan is given plenty of time to respond... which he doesn't. Again, demon brothel and the brooding roof's wonderful view must have been keeping him occupied for months.
Without reading later sources/retcons, it still seems like Illidan's fault, whether by sheer ruthlessness (worldwide slavery, murder and pillage) or incompetence in managing his follower, leading to catastrophic results. And even later sources cannot outright erase the slaverymurderpillage, they happened, just "seemed like a good idea at the time, by the way I really don't like demons, let's be friends". We have excellent reasons to depose "the lord of Outland".