All of µ's primary pokes that allowed her to dominate neutral now have early extended hitboxes before their active points. 2b also has an additional lingering hitbox after it loses its active frames.
Hakumen has always kept up in the matchup with his dominant normals and diagonal attack trajectories, not because of counters or his specific anti-zoning mechanics. It's his buttons that make the character strong and tough to fight. In the new game, µ's buttons have seen the wear and tear of time, especially with the loss of match-converting damage off major starters, whereas his damage mean has raised. This means it's going to be tougher for µ in neutral, and tougher for Hakumen on kockdown. I would say the matchup should stay about the same.