PS4 is probably going to have the advantage of more fight games later down the line, alongside Japanese games, etc. etc. in addition to practically every other Western developed game out there. Really there's no reason to get an Xbone unless you really like Halo, because that's the only actual, non-timed Xbone exclusive.
There's also Gears of War.
Although you mentioned Halo, there's The Master Chief Collection (Halo 1/2/3/ODST/4), Halo 5 and Halo Wars 2.
Fable: Legends (although this is kind of hard to get excited for given Fable's trend towards mediocrity)
State of Decay (although on PC and 360)
Zoo Tycoon (although on 360) :3
There aren't as many big franchise exclusives at the moment though I suppose.
To be honest though, I don't really mind. The types of Exclusives that PlayStation has are generally things I don't like.
I like my Xbox One. I'm comfortable with the console and the controller, happy with the state of Xbox Live, happy that most of my friends have Xboxes, and I'm happily embedded in my Gamertag/score.