It does sound a fun class, but I'll admit the dog model doesn't really give me the sort of Black Dog of folklore vibe I'd expect, and looks a bit like Scratch has gone for a swim in an oily pool. I'd have been tempted to use something more like the Shadow Mastiff model myself.
But still looking forward to hearing more about the subclass, and starting to ponder a character concept for it and the other new subclasses announced.