I like epiphany BUT you should be using your stars to help flesh out your core card collection before thinking about shiny cards. Vrock is a great card. Definitely get 2x if you don't have any. You also want to have lots of stars when good welcome rare cards show up. There are a lot of them, and 7500 a pop is pricey. Between the star store and core packs from leveling and weekend ranked, you should be able to gradually obtain all the core cards.