The shield pack helps a great deal with that. You can soak at least one rocket. Plus explosion resistance armor, and just hiding in cover and sniping them. I just unlocked the UAV booster and it helps a great deal bc you can see them from further away on your radar. Last night a teammate with the scout armor perk was using it to check our path for patrols as we advanced and that helped a lot, too. I also like the EMS mortar because the static field really fucks up the bots. And the Liberator Penetrator is really strong against them in open terrain because you can damage the lights and mediums from any angle and it's precise enough to dome the AT-ST pilots.