IMO gimmick = features, colors etc added to a particular shoe that is a carbon copy of something done in the past...in attempt to try and capitalize off of a past shoes success.
IMO i think the orange forging irons was a big time gimmick patterned after the galaxy IX.
cork, denim, GITD can all be considered a gimmick to some. but as long as its executed well, thats all that matters. (besides, i dont think the cork thing has ever been done before)
i also believe that the graffitis are a big time gimmick...but if the graffiti was placed on the same place that the honeycomb is on the SLH then it would have been executed much better and IMO been a good looking shoe