So having done a few extremes and dungeons with Dancer, I'm finding it hard to use Improvised Finish. I've noticed that after pressing Improvised, Improvised Finish isn't usable right away; it takes about a second or so before it lights up. This means that I can't weave it inbetween GCDs without clipping.
I figured it'd feel better to use it during downtime like a transition but that ended up not feeling good either. Turns out, having to spend ~12 seconds channeling to get 4 stacks means that's you have to choose between getting 4 stacks of Improv or starting Standard Step early.
Finally, whether Improv is at 0 stacks or 4 stacks, the shield just feels weak. Every time I use it, I feel a bit disappointed at how little it seems to help.