Scope of graphic features #489

Right now graphic features mostly map to pygfx buffers, except for present, deleted and thickness (for lines). I'm wondering what attributes we should and shouldn't make as "graphic features". For example, the current primitive legends take a label: str kwarg. If Graphic.name is a feature, the legend labels could automatically track any changes in the graphic name. But should other things like rotation and position also be a feature? Or should the users just use groups or make their own systems for keeping track of changes to things like name, rotation, position.