I would not give any credit to the previous manager. I would give credit to the previous GM, if that were the case here.
The White Sox have a pretty good team, a contending team, do you agree? The White Sox should be projected to finish at or near the top of their division next season, do you agree? And this would be the case despite who the manager is.
Therefore, if the White Sox don't contend, barring any serious injuries, I think it would be fair to question whether La Russa was the right choice. If the White Sox win the World Series next year, then La Russa will have been the right choice.