Ruckus with Wrecker can literally melt your shield! Formidable might be a good alternative to Aegis, since it gives you healing when your shield is abscent, but only once every 40 seconds, so enter the fight at the right time!
Do not rush the objective when there is a deadzone placed. This means playing passively and prioritising targets on the enemy team while waiting for the deadzone to disappear. Once it's gone, the team can group up and start to slowly cap the point.