The Nebulon-Bs and Imperial Lancer-class Frigates both share some similarities with the already-existing capital ships. Like the corvette and Imperial Star Destroyer, destroying components meant targeting their physical location and hammering them with missiles or lasers. Unlike other capital ships, though, you have to bring down the shields and armor before you can hit the component. Both the Neb-B and Lancer frigate have a very high recharge rate on their shields, which means attempting to whittle the shields down bit by bit won't work.
They also have some area defenses against fighters getting in too close. All of your weapons could get disabled; sometimes overloads were reset, etc..