For workflow and ease-of-use I think it would be a good feature to improve the handling of bringing up plugin editor windows (from Mixer).
Currently during my regular usage Cubase requires 2 clicks to bring a window forward - IMHO should only be one.
bring forward a plugin editor
open the mixer or arranger or other window (covering the plugin editor window)
now try to open the editor again from Mixer (for example). the plugin which is in the background still thinks it is in the forground so the editor first minimizes and on the 2nd click comes into the foreground.