Not just the fingers, but the wrists too. 
As written in OP, even if you eliminate clicks with mouse macros, you still need to swing the mouse around for targeting, so the QoL improvement is only slight.
As written in OP, in boss rooms with multiple enemies, especially high SR enemies, pulling multiple enemies will make it impossible to maintain DPS due to durability issues.
This is my main problem with the skill. Whenever I try to use it it ends up on the wrong enemy and does absolutely nothing, or it does end up on the right unit, but my other skills kill it fast enough that it still does virtually nothing. The tactic here is to put it on enemies you’re not attacking, but that’s very awkward imho and makes the debuff kinda useless.
wait, you’re giving me ideas. (or maybe that’s the caffeine and sugar.) it could just linger on dead enemies/prevent regular ones from going below 1hp for its duration. (if any of that were easier to implement than other more drastic changes.)
I tried it, but it was far inferior to the Aether version in terms of both damage and sustain.
Suggestion
I’m using a hybrid version of Allagast, killed Ravager and Callagadra and am quite happy with what I’ve built.