If I was to guess, I'd say people weren't used to it and built slower decks that would stalemate against the other guy's slow deck. I was walking around after my matches and would see games with five or six creatures up against five or six creatures on the other side and neither one willing or able to make the first move. My second two matches I dominated by having a faster moving deck. Also, very few people seemed to be playing red. Some heat rays and lightning strikes could have broken up those stalemates in a hurry. But everyone was all about either B/G or B/U.
A good number of cards did seem to have ridiculous casting costs but I haven't really compared to see if it's worse than 2014. The sealed format tends to make you use stuff that you wouldn't ordinarily use in standard play and every set had cards that are basically trash due to their cost.