Charli slays, Rita sorta slays, Nick is hot, Tinashe is hot and good, Meghan is adorable, and the rest are middling. They're exciting because they're fresh. We'll get tired of them as we did with other pop stars.
Ariana = New "Mariah"
Miley = New "Madonna"
Tinashe = New "Janet"
Not in the sense that they will mimic them artistically or in talent, but they will fill that void in the mainstream industry. They will prevail hopefully.