I don't think it's possible to create a new gaming mechanic in today's gaming landscape and still make an impact. Most of the games available today would have been derived from an existing genre.

In 2D, we already have platforming, run and gun, 1 on 1 fighting, scrolling beat 'em up, vertical shooter, horizontal shooter, isometric shooter, puzzle games, sports games, racing games and variants of these genres.

In the 3D era, we have the same genres as above, except they're now in 3D. The only unique contribution in 3D are first person shooters and third person shooters. Resident Evil 4 shook it up a bit with a close, over the shoulder shooting camera. Halo popularized the "rest to heal" mechanic and 2-weapon system. And Gears of War popularized the cover mechanic.

For a while, we had "alternative" games like the Konami rhythm games. We had dancing, guitar, drums, etc. But that genre also became stale due to overexposure by the Guitar Hero games.

I think the issue is that as gamers, we have been exposed to these gameplay concept for too long. That's why every once in a while, when something like Guitar Hero comes along, they become hits, because gamers want something new. But due to gamer fatigue, it also went out of style. Even God of War was considered unique for a while, until people got tired of the same mechanics. That's why the new God of War switched up the gameplay, so that it feels fresh again.

I do want to see something that excites me again, but it's getting tougher to do that.