I didn't realize we were only talking about games that ONLY appeared on next gen consoles. I think the term "next gen gameplay" is really just another way of saying "is it doing something new". People are getting all caught up on that wording for some reason.
And while Titanfall does share aspects of lots of FPS games, no game has ever combined them all into a package, and executed on all of those things so well. It's kind of like how Gears of War was heralded as a new thing it's cover shooter mechanics. But of course it wasn't the first game to do that, but it was the first game to nail it and bring it into this great overall package.
Probably not, but are you suggesting reviewers should grade on a curve? Uncharted 2 was most definitely a better game than Uncharted 1, but by the time Uncharted 3 arrived a lot of people commented on how it was kinda more of the same, and even do a few things worse than Uncharted 2.
Infamous 3 really doesn't seem to be doing anything new beyond the first two games, besides being really pretty. I think that is the simplest way to sum up some of the negativity in the reviews today.