Those general ass "___ you just ___" statements can make any game seem mediocre. "In Killzone you just shoot people", "In Street Fighter you just punch/kick people", "In Forza you just go forward." Like come on dog, we all know games offer more than that, but the way those offerings are presented, packaged, introduced, and implemented can greatly influence it's reception. Drivatars is an awesome mechanic and deserves it's props. That honestly is innovative, but it doesn't changed how Forza in the end plays out. You can take a feature like Drivatars out the game and Forza 5 can still be played the same, just with last-gen/stupid A.I. You try taking that cat suit or that Mario multiplier out of SM3DW and that game probably won't be able to be completed, because the levels are designed with certain power-ups being needed to complete them, and those power-ups greatly influence how you can trek through the world around you, especially if you're trying to fully discover/complete the game. Racing a "ghost" of my tendencies doesn't have the same effect on the game as Mario's new additions, so it's innovation doesn't compare to Mario's on that scale. Doesn't stop the game from being innovative, but IMO it's clear to see how Mario's innovations shape the game more than Forza's.
And honestly, Forza is the only next-gen game pushing great innovation between the PS4/X1. Battlefield heads have already admitted that BF4 isn't really innovative, 2k14 isn't really innovative, CoD/Assassins Creed are yearly rehashed cash cows at this point, and Killzone has always been back of the pack in terms of major shooters. A good amount of next-gen PS4/X1 games are honestly not innovative, it's just a case of good games becoming marginally better than your predecessor. And there really is nothing wrong with that, not every game needs to be innovative to be good/fun. Games that really/truly push the envelope don't really see the limelight like that too much because they sometimes cater to a niche audience.