DH 2016 isnt really much different than 2014. Glu needs to:
1. Stop having discrete versions but rather continuously evolves. i.e, no more DH 20xx - Just Deer Hunter, like Madden NFL Mobile or Racing Rivals. Who wants to start over every new version. I dont play 2016 for this reason alone and 2016 isnt different enough to start over.
2. PvP. Current PvP at a shooting range where you challenge a random non-real person is boring. Need to challenge real people, side-by-side, hunting in the same scenarios when you play the game. First to shoot the Deer wins or whoever shoots the most wins, etc. Allow team hunts/challenges.
3. Connection with the real world.
Sure, the animals and their surroundings are real enough, but Glu needs add REAL guns, bows, ammo, scopes, etc. Like a Marlin Model 336 or Winchester Model 70. Gamers can get deeper into the game if they can "live" in both worlds, leveraging their knowledge, weapon research, etc. There are plenty of rifles I see in hunting magazines that I can't afford in the real world but would love to hunt with them in DH. Gamers of Racing Rival know this, they appreciate using 'OFFICIALLY LICENSED' cars, not some made up variation. (oh, the guns and ammo should perform with the characteristics specified by the manufacturers). I could see it now, getting a notification about a "manufacture weapons update" and hunting with a rifle I saw in last months North American Whitetail maganize. DH has far more downloads as Racing Rival yet RR is grossing higher than DH -- reality is why.
Along the lines of being real, DH should add to the mix an additional 'real' features such as an option to maintain/clean weapon and failure to do so after so many rounds or shooting in stormy weather will results in malfunctions or increased inaccuracy (some guns being more sensitive). Bow should have ability to adjust tension... I could go on and on but I think you get the point. Hire an expert don't make it up yourself.
(A minor suggestion: a player should be penalized for letting a wounded animal escape)
Do this then you will have a hit game that will last because game details aren't fabricated non-sense.
Whatever you do, don't release another DH unless it's really different.