Engineer, useless?? If they are using any equipment, which they likely are, it gives away their position. You can see the equipment as they are throwing it out, including those frags that sometimes fall next to you silently, which you can now throw back with less risk. With an EMP grenade or Black Hat, you can take out so many things before they can do squat. I rake in a lot of points by just killing Betties and Shock Charges. Re-rolling your crap care package is just another perk.
Tac Mask is good too, but Engineer is FAR from worthless.
"Don't be single-minded. It will only serve to bind you later on." - Faust
I had a problem with them when I first started playing because I have to get used to all the levels, but after a while their no problem. People mostly put them in corners or door entryways so you just gotta avoid it. The only people I see die by them are rushers. They literally just run towards it without checking their surroundings so they deserve it.