From what I read, it wasn't even a type of wood that was banned. It's a maple bat, which is legal, but it's illegal if it's not dense enough. Maldonado would have had no way of knowing, because maple is one of the popular wood types in MLB and wouldn't have stuck out as different.

Lower density maple allowed for a bigger barrel profile while keeping it from swinging too heavy. This is just a preference. It's not an actual advantage because as long as you're using quality solid wood, every possible factor has a tradeoff. Players just swing what's comfortable and what compliments their approach at the plate.

Shit, I knew that was going to end up biting the Yankees in the ass as soon as I heard it. Houston trounced the Yanks all year, and while barely scraping through the ALDS, the fans at the Stadium chanted that. They were just asking for the big bad wolf to come blow their house down. Now Astros fans have ammo (on top of the actual postseason success) on the Yankees for a while.