I love how 90%+ of the people in this thread didn't read the OP. If they did, they would have noticed the words (Pokemon wise) after BCIF.
Keldeo may or may not see a rise in play after Plasma Gale, but imo Mewtwo will definitely get worse. Blastoise Keldeo currently gets destroyed by Mewtwo, but with the new BKEX that came out it can OHKO Mewtwo easily and its nearly impossible for Mewtwo to get the revenge KO. Something nobody has mentioned though is Darkrai-after all, if Keldeo needs it or Blastoise to function, and Darkrai needs nothing to function and has several metagame decks in which it is the main attacker, AND its more splashable, I'd say Darkrai is the BPCIF.
First off even if it regards the use of it pokemon wise it's just a tech, if it's played in it's own deck it has a better response play wise but still that doesn't change much regardless, black kyurem makes it even more as such so regardless its just a really good tech (you pretty much listed why it's not BCIF), darkrai bPcif, lol.