Hmm.
How well does Vigilance with Heavy Machine Gun or Flak work?
It should always be acting in support of a ship with either longer range or higher speed, so being kited shouldn't be too much of a threat. And a medium missile + point defense is a decent combination for an escort.
Poorly. There's no problem with the Vigilance being kited. None at all. The problem is it can't kite.
So if it is closing to ranges where the PD weapons are useful, it's taking damage to its shield. The shield isn't too impressive to begin with, so something like a Shrike can destroy it in one pass. Place PD weapons in the main mount, and other frigates will bully it.
Another issue is behavior. When surrounded by allied ships, the weapons will determine its behavior, and a standoff loadout will have the ship acting in a standoff fashion, but as frigates spread out over the course of combat, the standoff behavior matters less.
The ship is being pressed by multiple opponents, so it more or less acts like every other frigate, where speed is all that matters.
I've had good experience assigning the Vigilance as an escort to ships that are also supposed to serve as fire support. More aggressive ships are a no-go, as the escorts get isolated or tangled up with opposing ships, where they don't want to be.
Maybe the new DE missiles will make fire support more valuable? It seems the reason fleets spread out so much is avoiding the firing arcs of allies, and missiles can pass over allies to strike opponents. Great way to allow the Vigilance to sit behind other ships, where it wants to be.