Air Soldier+Cave of Wonders Guardian. The way they are worded, they lock the world. However, this isn't so bad, as it forces decks to run magic, Pan (as he blanks the air soldier), Herc, Beast, Minnie Mouse, or just actually use the escape action from the rulebook. In reality, this being a pseudo lock on a world is not a bad thing, and I'd say that we should just assume this is the case.
All of the "world" cards from set 4. I thought there was an intention with Leon, and Decisive Pumpkin seems right on, but then after reading Pegasus and Hades, it seems like someone really dropped the ball. This needs a ruling, post haste.
I think this may've been answered, but can 6 Peter Pan lvl 1's now be run, as it's a different card type? I would say no, but then this needs to extrapolate to Olympia, Oathkeeper, etc.
I think that having a choice between which Phil to use is a good idea, as there are benefits and detriments to both (assuming the "Olympus Coliseum" garbage gets taken care of).
And then, this is my personal beef with the rulings: New Pot Spider. It's been ruled that, for every one of these your opponent plays, you will lose 1 hp. If they play and replay so that they've played 6 of them, you lose 6 hp. Darkwing quoted the ruling he got from Jaffer, but the argument made is incredibly faulty. The claim is that the clause about the cards not being cumulative means that they are not recurring (you don't lose 1 from each every turn). Except that this is like needing to say that you don't activate Don lvl 4 every turn and search a magic card.
The Pot Spider has an entering play effect. It triggers ONLY when entering play, and then he is essentially blank thereafter. The ruling would be fine, if it weren't for the clause that they aren't cumulative (which means that they are not additive). This goes beyond Leon+Simba lvl 4, where we were basically told that in order for Simba to succeed, you need to only have 1 friend left, and thus must pick Leon. While most of us thought that was ridiculous, we accepted the reasoning and moved on. This is abusive and goes directly against the wording of the card.
Please add to the list.