Prophecy is a deck that requires a lot of skill and attention out of you. Veeeery high skill ceiling; one mistake, at ANY point, can cost you the game.
Infernities are pretty complex and you need to keep track of your resources. But you can get better with practice.
Other "difficult" decks include Harpies and Mermails.
Queen Wonderland
If I build a deck with every cheap trap card, fire hands and cie hands and every cheap summon monster and spell that is a sure fire way to win. Doesn't mean I am good. Just mean I have a sure fire deck.
...HAT?
Being good often means building good decks. Special snowflake decks don't make you better than others, and they don't win you nats. If you're so good, why limit yourself to bad archetypes?
Imagine a swordfight between two men. One guy's got a pretty well-forged sword with good, sturdy armor. The other is wearing paper-mache glitterarmor and wielding a knock-off katana.