For someone without a clue, there's no difference between Gunner and Engineer. Either can shoot, and if you don't know what ammunition is it doesn't make a difference.
I'd ask you to review this default, and change it to Engineer.
Unfortunately, no. We will not change this.
Giving someone a mallet and extinguisher won't make them more inclined to do engineering stuff. They will just jump on a gun. Why make them fail by not giving them all the Gunner perks from the get go?
The engineering game has an extremely high learning curve. The most common repair, HP repair, has a cooldown—we know this but no one else does. Every other game, repairing something means hitting it over and over again until HP goes up with each hit. Because of what players have previously been trained in, our engineering game is already setting them up to fail. Noobs will keep hitting the component and not understand why the HP isn't increasing while the cooldown takes place, or they just don't notice. Not until the cooldown finishes can more HP be added. In the worst case, the noob can stay whacking the component for a long time. This is detrimental for both the noob as well as the crew. Everyone is failing here and inevitably the noob will be blamed and yelled at for being a shitty engineer. The only case where previous knowledge is useful is when rebuilding. However, tools have different specs for HP and rebuild. That's how the engineering game was designed. It's fairly high level strategic/tactical play vs. twitch reactions of a gunner.