Coming to the original question ...
It is my strict personal opinion that BD players are not a good replacement for media players. While BD players can play back media from the HDD, some may place restrictions. The menu will be very rudimentary and little cumbersome. BD player is best suited for regular BD/DVD watchers with occassional downloads while media player is best suited for downloaders. But one thing where BD player scores over media player is that while a BD player can play discs, a media player can't (except Dune).