For a little time I saw Manectric and PLF Kyurem in the same deck, but I'm only relating it to this format (XY-BKT). I can't really see the AOR Kyurem EX being used in that deck though. Glaciate is hard to pull off and does little damage as well needing two and three water plus a colorless energy for the other attack is not easy nor worth it. Regice, Articuno, Raikou, and Regirock all can be ran in here with a 3 energy cost and attacks are doing a better effect and/or more damage. They are also not giving up two prizes and most of those Pokemon can attack with a DCE/more colorless energy.
The one from Plasma Blast was actually the one I was referring to. It was the only thing in the deck that could OHKO stuff, and you could use it's other attack for just a DCE, so it wasn't totally useless without M Manectric set up. Totally agree with you on Kyurem EX from Ancient Origins, and that none of them are really relevant to the current format.