In Creo View 4.1 there is a setting in Creo View options (Defaults/ Drawing Viewer/ Lock Annotation Size when zooming) that affects the annotations that you have created. When locked, the annotations you've created IN DRAWING VIEW will scale up and down when you zoom in and out. When unlocked, the annotations remain the same size while zooming. But the same is not true when viewing a model.
I would like to propose that functionality for Creo View Model View.