Worst engineer trait that is affecting the balance of the entire game is getting so many rockets on spawn. Back in my day engies got 2 rockets and we still managed to kill armor effectively. This is also affecting Air balance, because getting 5 rockets means air is constantly in danger from a single engi.
Likewise, it also means the rockets have to suck because you get 5. AA rockets are in a league of their own with how useless they are. Against a skilled helo pilot, an AA rocket will never land. They can abuse targeting floors, how broken flares are, the spawn AWAC being completely overtuned and too effective. Against a noob pilot, 2 seconds and they're blown out of the sky. Then ya'll listen to the baby ragers about how RPG is broken when in reality it's just the only real option against helos.
Other changes? They should get the rocket defense gadget that support currently has. Never made sense to me why support would have that gadget when it's clearly best used to support armor.
The supply crate I have seen used more to block routes or make cover than to actually resupply armor. I think if it could be replenished... natively? through a timer? What do you call that... without an ammo pack, it would be far more useful. Currently even if you try to use it, armor won't open their eyes and just drive off, and then you just have no useful gadget again until you die. Or you toss it near them, then they move and barely touch it, breaking it, then again you have no useful gadget.
You also need to fix damage somehow traveling through armor to hit engies behind said armor. I'll be behind an MBT, an IFV is shooting the MBTs nose, and I die from explosive damage. What? Why? I also notice this happens with console players FAR more often than with PC, so I have just chalked it up to console advantage. But this isn't an engineer issue, it's a gameplay issue.
SMG's are often more accurate than an LMG at range and keep a reasonable damage profile at range as well. Pretty silly if you ask me. An SMG should rip close range, and suck long. Currently, they're just consistently good across all ranges. Though, aside from a damage profile nerf, SMG isn't in that horrible of a place. I think almost every LMG needs a substantial buff.
Torch feels weak. In many cases, one engi dealing damage to armor can outpace the engi repairing armor. If the tank doesn't take self-repair, then 2 players will always lose against 1 player. To me, that seems broken. I feel like having multiple engies repairing shouldn't be as strong though, and additional repairs over the 1 should have 50% reduced effectiveness. The armor has a responsibility to find safety instead of just having 6 engis spray painting new flames on his tank nullifying all damage.
As always, change the passives to be always active instead of some silly "earn score to unlock" CoD Trash BS garbage mechanic. Actives should go away.