while it's true that a new employee brings in outside knowledge, it is also true that a new-comer tend to propose solutions to problems that seem obvious at first, but is then stuck with some organizational quirk or problem that prevents nice solutions from working (and find out that years ago, someone else has already proposed something very similar and it either failed or didn't work).
Old tribal knowledge is as important as new perspective.
Old tribal knowledge is as important as new perspective.