For what we know about right now i sadly have to say Destiny since everybody seems so hyped for it. For me personally i say AC Unity, Infamous Second Son or if we are lucky X

From what's already been released, I'd probably say Titanfall, as hype amassing around it was pretty massive for a while. It's also been generally highly viewed by a lot of critics. It wouldn't be my choice, but I could see the critics thinking of it. From what's on the horizon I think The Order stands a chance.
I don't think there's really a clear front-runner in the vein of The Last of Us from last year...

Sunset Overdrive will be decently well-reviewed, but reeks of a commercial flop.

It's similar in ways to the Wonderful 101 in more ways than one.

A ground breaking, creative studio. Platinum games, check. Insomniac, check.
With commercial difficulty. Platinum games, check. Insomniac, check.
White-knighted on a single platform. WiiU, check. XOne, check.
Vibrant artstyle, tongue-in-cheek humor. TW101, check. Sunset Overdrive, check.
In a genre reviewers/gamers increasingly don't appreciate much (action/platformer). TW101, check. Sunset Overdrive, check.

No way, SO actually has massive hype behind it? Have you not seen the reactions today?

Lost count of how much positive feedback I've seen. MS are advertising it as well, that negates everything you said.

Maybe X, Smash Bros. or Sunset OverDrive.

Then again there's a good chance it could be a whole heap of games.

Destiny seems the logical choice, but I think it'll get a lot of clickbait troll reviews trying to go against popular opinion. That may drag it down enough to allow something else take it. Wouldn't be surprised if an indie title surprises people and wins some awards.

One commercial on at 3 am on espn four during a fishing show and SO will have received infinitely more advertising than 101 ever got.

Yeah that's happened before, is anything on the horizon that looks incredible tho?

Ehh... there's always pockets of "massive" hype for most any system exclusive made by a company worth writing home about.

Regardless of whether or not MS actually advertises the game doesn't negate the two game's similarities. If anything, MS's backing only ensures the game doesn't flop as bad as TW101 did. Still -- I see the game struggling to pass 1 million units and getting lost in the shuffle of several very big releases.

Transistor maybe.  Super Giant Games is coming off the success of Bastion so it could potentially get enough attention to get some consideration at least.