It's a fun card to play around with in Casual. I don't trust it on ladder, though--too RNG. Omni was talking about it in their last episode, as well.
I'm dust poor again... What classes are just always trash? I truly hate playing Priest, so those cards are gone... Would only focusing on Hunter, Mage, Rogue, and Warrior be okay? Or should I not dust Shaman or Warlock, either?
Well she's pretty much just meant for control mirrors and surviving fatigue, you just hope to get something good from it.
Dusting stuff is completely up to you. No one can tell you which classes you're gonna enjoy. I'm not shy about my absolute hatred for Priest, but I'd be lying if I said I didn't enjoy causing misery on my journey to the golden Priest portrait. Super fun class to play as.
Shaman is the other class I really don't like, but I'm kinda enjoying it at the moment.
I also used to find Hunter incredibly boring, but eventually came across decks I liked.
So you never know when your mind might change, but if you're really set on not playing a class and you don't think you'll regret it, then dust them.
Edit: also to answer your question, I don't think there's any class that's always trash. Every class has terrorized the meta at some point. I think Mage might be the only class that hasn't, at least since I've been playing.