I think the rounded edges and shadows can be a nice touch for certain websites / blogs. Cross browser would be very nice!
Would it be hard to work some Theme Options into PivotX as is common for Wordpress? That way you could maybe let a user (I imagine less code-wise people) switch from a 'regular' theme to your shiny rounded one. I imagine this is only a change of CSS but wouldn't it be nice if someone could just thick or unthick this?