I don't see it as a problem. I don't even see it as any type of concern. But the amount of staff leaving at the same time isn't a coincidence, bettering their career opportunities? all at the same time? Nah, I don't buy that announcement, but for professionalism sake you have to respect it and take your hats off to them. In anycase, I belive the changes are needed here rather than there.
But yeah, They'll be replaced easy enough. It's always the case, one steps down there will be someone else there to replace him/her.