The addition of a toolbar inside the ModelBuilder view is a fantastic addition.
I would appreciate the ability to customize it some, as in ArcMap. It would also be nice to remove things I don't use very often to save space and make smaller windows easier to use - buttons start hiding themselves pretty quickly.
Related: ArcGIS Pro: Option to Enable Dockable Toolbars and... - Esri Community
Include ribbon, QAT with floating views - Esri Community