Shifts aren't strictly 45 degrees. Also, a 338 dash, while possible for an S starter, is impossible to use otherwise (aka 99% of the time in PvP) unless you're on a wall.
Your shift up will either cause you to be way too far to the enemy (and thus hitting it out of range by the time you reach the red A), or cause you to be off to the side, making your Cross Cut cancel (Space) miss.
EDIT: I also recommend denoting the number of hits on skills that are canceled early. For example, Cross Cut is often canceled with only 1 hit.