Each of those players mentioned earned their place in the final by winning six best of five matches in a row. They probaly knocked out some high seeded players on their way. They were healthy and played their best tennis before the final. Why would they suddenly be easy opponents in the final?
Sure they played well to get there, but experiene is one of the most important factors in a Grand Slam final and you can ask anyone on the tour and I'm sure they'd rather play an unseeded player in the final than Djokovic or Federer.