I wonder if it's possible to make iaijutsu behave like stardiver in reverse. If you don't know, stardiver has a strong animation lock that absolutely prevents it from being weaved with any other oGCD. If they applied a strong animation lock to the sheathed part of iaijutsu and then made it free up the moment you release it and kept the gcd timing upon release, they could preserve the feel of the ability while also removing the cast bar.

I don't care either way, I like how the cast bar feels with the build up to the release of the iaijutsu. I don't think there is a skill expression to it and I don't think it is the only way to achieve the feeling the cast bar provides.