this should make my next comment that a significant increase in graphics from one gen to the next doesn't qualify as a gimmick, make more sense.
Yeah, your definition of a gimmick is simply based on graphics, not how games are played. Seriously, how much better are games going to look in the future? There was hardly that much of a leap between the XBox and the XBox 360 as far as graphics are concerned. Sure they're slightly better, but compared to the jump between the SNES and the N64, the jump isn't noticeable. Those new graphics don't change the gameplay.
A gimmick is something that is completely unnecessary to the gameplay and doesn't improve it in the slightest. That is as simple as saying just because it has better graphics means its the better game.
There's a reason why this console generation has continued much longer than any of the others. Graphical limitations are starting to level out. Everyone but you knows this.