The three main errors I see described as 'double prints' are
This means you could drop a land and a few Mox, then trade your hand in for a brand new one on your first turn, and leaving your opponent with a potentially bad hand.
I've caught Pokemon trading card fever
If leaving it up to chance on packs and retail listings isn't what you want, you can always buy single Pokmon cards from websites like TCGPlayer or eBay, where a variety of third-party collectors are looking to sell their great pulls
Graveyard hate is something most decks want to devote at least a slot or two to, and having it stapled onto a highly playable card is a win-win
Everything was ready for Kozmos to be combined with them in my opinion, and while I probably dont have the optimal build for the deck, I would not be surprised to see similar styled builds at high level events in the future but with more optimized engines