I have started developing the new version 5 of the Semi-Automatic Classification Plugin for QGIS.
This will be a major updated with several new functions and a revamped interface.
In particular, the interface will have a unified dock (merging the ROI dock and Classification dock of the previous version) to gain more space for the display of the image. Also, several tools will be moved to a toolbar for rapid access to ROI creation and classification previews.
Following a preview of the new interface (there could be changes in the final version of SCP).