I don't think the quality of Hamasaki's PVs has changed much over her career, her recent style just doesn't suit your tastes.
The kind of PVs I like most are concerts. Just the singer and the music. I also like videos with interesting effects, scenery, or animation, like M -above & beyond- and Connected. I generally find the kind of PVs with acting and plots (which most people seem to like
), especially Ayu's, ridiculous.