Hmm, I'm not too concerned about the face down monsters. I haven't seen as many and you can always keep a NOE in the side board just in case. I would rather see a Mystic Swordsman 2 or 4 in the mix just because
Drillroid doesn't prevent the flip, which makes things pointless when you're trying to prevent the flippers.
IMO, my favorite face down prevention is
Ceasefire, because it does damage, negates any flipping potential, uses your effect monstetrs as well in damage calculation, and then opens teh door for some safe trampling.