The rules of the game have morphed and grown in complexity
Well break this up into three categories: Sure Thing, Situational, and Sleeper Hit
Popularity of the Pokmon: Pikachu, Charizard, and Legendary Pokmon are almost always in higher demand, regardless of their in-game strength
The recent Reloaded Fire King structure deck is a particularly impressive release, promising a deck that can compete in tournament events just by picking up three copies of the deck and merging them together
Purphoros, Bronze-Blooded was probably my least favorite god from Theros Beyond Death , but it still has value in accelerating your creatures
Commander and maybe standard players will like it more, but it looks like there won't be too much demand for such an expensive planeswalker