Technically, he doesn't say it is all creatures. He says it is "...all-creature themed..."
Personally, I think there has been enough speculation and enough talk to think that it is indeed all creature. Anything that would have been an instant has been put into a "when this is turned over" instead.
But...if it's not all creature, he can't be accused of lying, either.
What I like is when he says, "...Tradewind was never played primarily for his ability to block...", indicating that the lower toughness is largely unimportant. Please, Mike, I remember a time when a burn spell was considered inadequate unless it could deal 4 damage to a blue creature specifically because of Tradewind Rider. Temporal Adept, for example, sees play, but nothing compared to what the Tradewind did.
