Miley has one of my favourite voices. Obviously she was an actress before she was a singer, and she brings that idea of performance to her style of singing - she's really good at knowing where to land the stresses, where to push her voice and where to relax it, how to sell the idea of a song and what it's about.
I love that when she did her inevitable "I'm a sexy adult now" transformation she used the focus on her image and sexuality to distract from the fact that so much of her music was relentlessly and unashamedly pro-drugs, and nobody really noticed because everyne was too busy being scandalised by her appearing naked in a music video.
I'm not sure she's bringing rock back or in that heritage version is referring to - I think she's a cultural magpie and she borrows from wherever if it might be interesting. She's done duets with Britney and Nelly, but also her dad and Dolly Parton too, and she recorded an album with the Flaming Lips. I don't think she has a clear sonic identity, which on one hand makes her thrillingly unpredictable to follow but on the other means there's no sense of who she is consistently and I think that the genre-hopping is why she isn't really elevated like some of her peers.