I hope this is not a repost
While you are flying above the dead scar and you have to kill the Pitlords and the Eredar Mages and the other demons you can make it a way easier.
Usually you can throw just one single arcane bomb. But if you bind the bomb on a hotkey (like "1") and click on the ground where the bomb shall impact, you can do it again right after it (it must happen rapidly).
If you are fast enough you can throw two bombs or maybe even three!
Sorry for my bad English : /