I assume you were talking about consistency of sound throughout her career and not quality. Eitherway I've always felt like she's tried to expand the dynamic of her music and adding more layers with each release. Arular was very flat sounding but trying to have as much going on and bouncy as possible. Kala was a fuller and fresher version of that sound by tons of different styles and flavours. Maya was almost bomb squad-like by trying to stack as many sounds and effects on top of each other as possible on some songs (Particularly Tequila and Steppin Up). But most fans especially the ones who only like Arular just want fun bouncy beats