For melee it is.
For rogue goblin is extremely useful, troll and orc are very useful, UD, we'll it's nice ignoring any bar that says "Fear", Blood elf get intel, more enchanting, and a silence.. Any melee class would be good with that silence, but that doesn't mean it is the best for a rogue >.> eng bombs are as, if not more useful than the BE silence...
I disagree with the bomb statement. AC restores 15 energy for more dps, silences for 2 seconds as well as interrupts even if silence DR is up, it's instant which means you dont have to stand still and cast it, and you dont have to choose a place to put it, where someone could easily move out of in the time it takes to cast a bomb.