If we make a good hire, a coach that can install a system for the players he has that doesn't require 10,000 reps and a body transformation to run we are 10 wins and conference contenders immediately.
Irrega'rdless of all other factors, we are still the second or third most talented team in the conference, most talented team in the division. A coach that isn't terrible can trip his way to 10 wins using the NCAA video game playbook.
We probably aren't good enough to beat fsu or clemson in an acc championship, and aren't running the table so ACC title and playoffs are out year 1, but that type of success should be the expectation by year three on the next hire.