I am an Engineer.
That means I use an SMG.
That means I shove myself up my tanker's behind.
That means I go down with the tank.
That means I waste my time firing rockets at an enemy tank, only for it to recover all the same, for their engineer is also up his tanker's rear, and he and I are both alone, for everyone else including the tankers are playing Support with M4's.
It is a painful life, but I would not change a single thing.