I'd much rather take Evocators tbh, but I'll wait for the full warscroll before giving my final judgement. I'm curious what other utilities they can bring and what points value they are at. If they are within Evocator range and this is all they offer damage wise, there's little reason to bring Annihilators.
More importantly as a Ironjaw's player, I wanna see the new Orruk's and what specialties they bring to the table. Orruk's Warclan side, if they can patch up the Brute's warscroll a bit and their points if need be, that's all I need to be happy.