I don't know about others but the amount of times I've accidentally left a squad while urgently trying to use a squad power makes me cringe. Maybe I'm not the paragon of squad lead competence but still, if I need to leave a squad I do it through the c menu whether I'm lead or just a squad member.
I bind squad powers to mouse 4 and 5 for max efficiency, but I really don't see why the leave squad button is on the fmenu, when would you ever use it? Better to put something else in that spot, like "regroup to me" or something, I don't know.
being redone since the dawn of time a nice fix until that never-happening redo is to replace the leaving squad option with voting to kick squad leader