I don't think Kyurem's that bad, getting rid of Mewtwo's and Giga's DCE's could hurt. You can only have 4 after all. You can just switch + retreat to keep using Hail Blizzard and even then the combination of Ice Wing + Hail Blizzard is 180, which is lookin like it's going to be a magic number. It's got relatively strong early game, ESPECIALLY if you go first, because it can turn 2 60, and take an energy off your opponent's active trying to set up.
And gigas can one shot ANYTHING, but it also puts you in range of losing 2 prizes pretty easily. I don't know, I think the hype is in the wrong place.
(All 3 EXs would make for awesome tank decks though.)