Dabo beat South Carolina in his interim year and had his team in the ACC Championship during his first full year and won it by his 3rd full year.
If Leach gets us to Atlanta and wins it, then yes, it's easier to overlook a 3rd straight Ole Miss loss.
Overlooking the laughability of comparing Ole Miss to Ohio State, Harbaugh won the Citrus Bowl and had his team right outside the top ten during his first season and in a NY6 bowl in season 2.
If Leach had done that while losing to Ole Miss, then yes, it would be easier to overlook the Ole Miss loss.
The problem is that Leach has lost to Ole Miss twice, but hasn't taken the team to Atlanta, much less win there, and he hasn't gotten the team into a NY6, so if he loses to Ole Miss for a third time, he doesn't have the positive data points that Dabo and Harbaugh did during their first two years. I also checked and neither of them lost to Memphis.