My personal opinion on F-Hisui so far is nothing great.
Her normals look sweet but seeing them in action they don't seem to work; I've seen a j.lamp jump in simply whiffing for no reason, which leads me to believe the hitbox on it is really iffy. Ex ladder and the other variations might end up being a good anti air but nothing more, and anti airs isn't something Hisui has been lacking. Office chair... how does that help you when they can simply poke it and it's now THEIR office chair. Throne is cool though.
To be fair there hasn't been much F-Hisui footage uploaded so far and all of it was by people who had no idea how to play that version of the character, so it's very possible if not certain that my opinion will change as people find out how to play her correctly, and I'm really anxious to see how she evolves. But for now I can't say I'm thrilled by what I've seen and C-Hisui will remain my Hisui.