On Bridge, I usually take Sparks and go to the building opposite of the generator. You can barely see the generator’s edge from there, people can’t hit you from inside, especially if your team is lemming’ing in.
However, as Sparks you don’ have to aim for the generator, you can also aim for a dead lemming. The defenders will have to reload eventually, especially if they blow half their ammo into the dead rising.
I don’t think that any other merc can do that job more efficient.
Granted, this is the only vital generator that is safely positioned for destruction at the moment, so it might stay after all.
It’s similar defending against an EV - you’re charged most of the time anyways, if your team doesn’t insist on dying far out of sight, you have an easy time. This job is more efficient with Skyhammer, Arty or Kira, so I guess it’s alright.