Dusk Vigil never actually shoots its Fusillade

Because Ember Fusillade adds a new ember each time it is cast, and only shoots them if none are added for a while, if you are casting constant with Dust Vigil (which you almost certainly would be), it just keeps adding embers once capped (not actually adding them, just refreshing the shoot timer) and never actually shoots them. This effectively makes the unique useless.

You need to stack reduce skill duration to make it work as it affect the hovering duration. But regardless, without a +lvl to All/Fire skills I don't see that Unique viable imo as +lvl is almost the only way to scale properly spells focus build.

That being said, it's a good leveling staff at least.

No idea how people manage to build around ember fusillage, as it punishes player for casting faster. If a skill is not suited for mashing, its not suited for poe endgame.

Amount of not-yet-killed elemental spells is woefully small. GGG either decides it should have 15s cooldown, or should have an opposite element infusion (apparently every player wants 3 element build), or outright gates with unique mechanic like poor incinerate.