This is the same question that was posed by the Donatists to St. Augustine. "We have the same sacraments, we hold to the same councils, do we not have the same faith?" Pandering for notions of validity always makes me think of the episcopi vagantes, needing to be recognized is a mark of being schismatic.
Some jurisdictions don't accept RC baptisms while others don't even ordain RC priests who convert so it's a matter of the individual Orthodox Bishop's discretion. However, if the Pope of Rome were to return to Orthodoxy tomorrow, would every person in the communion be baptized? Probably not. Would every bishop, priest and deacon be ordained? Probably not. In the end the issue is not of valid or invalid sacraments but of schism.