The Shepherd is an early game favorite, with its nice logistics features, and it's drone wing that increases frigate survivability.
Late game, it tends to be dropped because it just can't contribute meaningfully. And this makes sense, it's a civilian ship, easily outclassed by hulls designed for war.
But the Shepherd plays a nice and unique role on the battlefield, as a fast, long range support that protects it's allies. And it's kind of a shame that there is nothing to properly replace it.
Why not give the Vigilance a defensive drone wing, and allow it to be the stronger, more expensive bigger brother to the shepherd? Let it keep both mounts, and stay chronically allergic to small amounts of damage.
Mining pods could work, but I like the idea of special defensive drones designed to body-block vulnerable allies. Fast and tough, but in wings of 3 with nothing but Vulcans, or maybe PD lasers. Something with decent deployment range, that can soak up quite a bit of damage and deter fighters. But with firepower that most frigates can safely ignore.
By default, the Vigilance AI could automatically target overloaded allies for drone escorts. This would give the Vigilance a strong and useful niche well into the late game, without it robbing the strengths of any of the other frigates.
It could also encourage more use of frigates in the late game, since it could usually keep up and improve frigate survivability.