Most digital painting software use dockers and panels for tools. Someone mentioned Krita with Pie Menu like Blender. I think a problem would be that Pie Menus are very good for keyboard and mouse control and not so much for keyboard and tablet. However, if one or few Pie Menus could be used as quick access tool when working in Canvas Mode, it could be very helpful. It will be what the KanvasBuddy add-on is trying to accomplish.
I have a small screen and I generally paint in Canvas Mode. So I have to frequently tab out to access Layers and other dockers. KanvasBuddy helps with some of those issues, but a native tool for a sort of Quick Access Hub would be cool.
I tried making some mockups.
