It was amazing for battlegrounds and world pvp until they nerfed the shit out of it, and then eventually removed it. I remember when cataclysm launched you could engineer bombs that hit for everyone’s entire hit point pool, and then stand above the graveyard at Warsong Gulch, wait for everyone to spawn, and insta-kill all of them. It was hilarious. Of course the bombs were stupid expensive to craft, so you’d only do it a couple of times for the lulz.