Yeah, Imperial defectors was a plot point in some old SW stuff too, although not to the extent I think Disney mined it IMO. Even some of the recent Lego stuff too.

Even some familiar movie characters, like Wedge, were retconned to have been former Imperials where they weren't before. While of course Han, Biggs, Madine, Hobbie etc. Imperial past was also old EU canon (Based pretty much on some early story notes that formed some of the old EU's early backbone), I don't think Wedge was at all...