I disagree with the consensus. What is your goal, and why do you play engineer? Are you:

1) Trying to keep the team alive and doing their job?

Or 2) Only engineer because you can heal yourself.

In the case of (1), protection IS worth it. Your teamates will spend less time wondering if they will have to use stims, and more time using their skills. Without protection they will be concentrating on staying alive, wondering when they will have to spam stims next. You are trying to help the tanks, not make them leave because they ran out of stims.

You can attempt to overheal, but you will most likely not be able to keep up. I've seen it when on my alts too many times. The only thing that annoys me more than an engineer without protection is one that doesn't heal.

In the case of (2) then you should probably play another class or go back to PL. You are obvoiusly infected with PL mage syndrome, and engineers are NOT mages.

Seriously though... what else are you going to spend the skill points on? Shield rarely lasts long enough to regen the energy spent, making it worthless. Pain doesn't benefit much from extra points. Sonic boom has a rediculous cooldown. The first skill is ok now, but you can get it to a decent level without dropping protection. Leech doesn't heal enough at high levels to be considered, imo. So that leaves supression, which can be useful in rare occasions. Mostly it is just annoying because it changes your target, and the first aoe will cancel it out anyway.