Perhaps, as with other identifiable styles, it is limited in its capacity to portray and provoke response due to repetition and consequent saturation of its audience. Then again, I find it odd that certain works continue to captivate long after a given "style" has passed from the stage, undoubtedly due to the skill of the practioner.
Also, I wouldn't agree that instability in abstract expressionist/impressionist imagery conveys only emotion. The "ink blot" effect (not unlike cloud watching) provokes shifting visuals in works of note in much the same way that the well-rendered written word provokes shifting visuals. I would go so far as to say that expanding visual associations on repeated viewings is what sets apart the successful work from the poseur.
Well said.