For example, this would allow me to create week-long phases which would be 5 days (and not 7 days). A milestone would also automatically be populated on the first business day available.
Related to this, I would like to be able to create templates of phases and milestones that only take into account business days
Weekends are now automatically excluded from release templates in Aha! Roadmaps — so you can focus on business days between phases and milestones.