Of note, the Eraser Shift plugin is already a very capable plugin. I think that if @EyeOdin manages to add toolswitching functionality (from the current active tool to the brush tool for both the eraser and brush mode) there really isn’t much more that this feature request could bring over his amazing plugin, other than a tool button in the tools perhaps.
The toolswitching to a brush tool is also what I miss from the threeslots addon, if I recall correctly. I’m mostly using canvas input settings to adapt to not switching tools 