First Kartana GX and now Mismagius. There seems to be a lot of anti-special energy coming into the game, and they are both incredibly playable in already playable decks. I never imagined that they would make playing Sycamore a disadvantage against any deck. If you hold onto too many cards to avoid Trashalanche building up, then you're just going to get smacked by Black Magic instead. Weakness to Darkness is kind of bad, more so in expanded, but there needs to be checks & balances so it's fine.
I almost want to like Xerneas since it is an option to search for supporters with a full bench, colorless so you can put it in any deck, but this card has little value so long as N exists in the game.
Any Octillery that isn't Abyssal Hand Octillery is IMO not worth playing, and the attack requirement is horrible usage of special energy. There's no reason to use a Rainbow or Splash Energy on this to attack for 120. There are much better attackers.