I ran around as an engineer (was a recruit to start) and had fun shooting people in the face with the shotgun. I'm on the PC on normal difficulty, but I didn't really find it that hard.
I took some pistol skill to get the cover shooting as well, for more stealthy takedowns.
I think Fallen Ghost is exaggerating personally. Also, while I can agree that the game should have told you about sabotage level 1, I also think that people should actually take the time to read the skills. But hey, I'm weird like that.