Probably trackers are very sensible programs for GUI/edit mode changes since they are so so highly keyboard dependent.
You need to memorize lot of key shortcuts, you have to build a window diagraman in your mind about what keys you have to press for open certain windows or do certain edition works. Finally you maintain that "diagram" on your head, for years of tracker usage, and its really hard to change things that are "written in fire" over your way of think about "edit with trackers".
Programs that rely on mouse for edition, doesnt give so much troubles for users when they move from one to another program.
Image programs: Photoshop, corel, gimp, paint, etc.. they rely on mouse movement for edition. Maybe some menus changes but usage of the program is about the same.
Video programs: Vegas, Premiere, etc.. They rely on mouse and drag and drop sequences over horizontal bloqs... Exactly same programs with different menus. etc... the edition is always the same..
Midi sequencers: Logic, Cubase, Cakewalk, sonar, etc... They rely on mouse and a piano roll for enter notes and move events with the mouse ... Again .. same program but with different menus and options. Edition is the same. Same mouse movements
Im not saying that trackers should move to highly mouse usage.. Im noticing that moving from one tracker to another is not only a problem of get used to different menu layout or windows. It implies different way to think and try to erase a way of think that you used for years and its totally different now.
As example: If video/midi sequencers will replace the piano roll(horizontal) layout by a patterns (vertical) one .. jumping along these programs would not be so easy for users. They would have headaches, and would not want to change program neither.