We've had this debate. Link Wray used distortion as opposed to feedback. But in retrospect I don't think the feedback thing is any big deal. Can anyone name any other feedback songs? Hardly a trend setter, it's really just a novelty, whereas Link's distortion paves the way for Hendrix and the like.
I guess we could argue that the feedback thing showed that pop/rock records could have unusal sounds/effects, but this was probably already done. It showed The Beatles and Martin had imagination I guess.