let's not
The required stillness of Iaijutsu is what allows the skill to be this strong too and have no cooldown. Make Samurai able to move freely for it's whole rotation and you take away a part of its complexity. I mean, you take away the good part. Bad part is still tsubame optimization. It gets so important to know how to use this skill properly on some fights that requires heavy movement, removing the cast time would just make the class way too strong imo. It's a bit like dragoon jumps making them die in an aoe. You die if you don't plan properly ahead. Or ninjas using ten chi jin. This just pulls us closer to monk, making us a better monk in fact. And that we don't wanna, seeing how few peoples play monk right now.
Yes they removed the cast time of Tsubame, but that was mostly because two whole GCDs of stillness is not possible for a melee, especially since you can't delay the second one.