Coming back to the game last fall, after over a decade break, I was very sad to see that the disadvantages offered so little in the way of role-playing and were simply there to hurt the characters. Anything that adds more RP chances in the form of disadvantages would be great. SR could certainly learn a lot from some of the other systems.
As much as I can agree with you on this, I've never felt that SR really rewarded roleplaying as much as more fluid systems do. I think it'd be easy enough to throw in some really simple ones though, and I expect
Run Faster will have a whole slew of new positive and negative qualities. Some really basic ones could be color blindness, a verbal defect (lisping or stuttering), and daydreaming. Those might be worth about a point or two of Karma, and only require the player to roleplay the related negative qualities.