In 2 and 3, at least, engineer is a support job. You're best off with a heavy hitter like Grunt to distract enemies while you set up your turrets and snipe from a distance, using tech powers to steal enemy constructs and take down defenses (and also overload flamethrowers, it never gets old).
Plus Grunt gets all that extra dialogue from the Blood Pack during the Recruit Archangel mission, so it's worth grabbing him for that anyway.
Plus Grunt gets all that extra dialogue from the Blood Pack during the Recruit Archangel mission, so it's worth grabbing him for that anyway.