Besides Garrosh's unexpected change of heart, this quest -- more specifically, quest line -- centered around The Bomb is actually quite fascinating.
As a Goblin character in Kezan, you had to do the quest Waltz Right In for Slinky Sharpshiv. In it, you had to steal Trade Prince Gallywix's prized possessions with the hopes of reselling them and making big moolah. The 3 possessions were Maldy's Falcon, The Goblin Lisa and... The Ultimate Bomb? Hold on a second... a super secret bomb being worked on by Hobart Grapplehammer? That sounds awfully familiar.
Further down the line while in Azshara, you have to deliver an unstable Azsharite Core from Hobart's Secret Lab to his assistant, Greely, in the quest Segmentation Fault: Core Dumped. Being the decent Goblin he is, Dr. Grapplehammer manages to weaponize the unstable core and then gives you the task of delivering it to Bilgewater Harbor in the quest A Hello to Arms. Assuming Hobart is trying to finish his work from Kezan, the Armed Azsharite Core is the continuation of his "Ultimate Bomb".
Lo and behold, after a pit stop in Ashenvale, failed interventions from the Alliance and a refueling session, this bomb is finally dropped over Thal'darah Grove in this very quest. So basically, Hobart Grapplehammer built a nuke out of Cliff Giant poop, sent it to an insane Overlord who then used it to destroy a grove full of innocent Druids. Oh, how I love Blizzard.