QGraphsView could provide plotArea like ChartView.

This is important to interact via the mouse with the axis.

For the public method QRectF seriesRect() const should be invokable from QML, i.e. : 

Q_INVOKABLE QRectF seriesRect() const

 
Furthermore, providing more direct access to the position of each axis could enhance efficiency (in case of several axis on the same side). For instance, the axis renderer could set position parameters directly within the abstract axis object.