Catalyst's Ultimate is pretty useless

Your suggestion is way too overpowered, but some other suggestions are to allow the pressing of x to switch directions of the ferroluid when preparing to use it, like press x to make the wall come up horizontally in front of you, and to switch your fluid shot from vertical to horizontal. A possible buff to her wall would be to deal slight damage similar to her spike strips spikes could show through wall when enemies are near so the user knows where to shoot too possibly so you aren't also negatively impacted by your own allies ult.