There's a few things I think would be nice to have in the new game, assuming it really is a hunting sim/game.
Third person or at least a trophy shot mode.
A clothing system similar to The Hunter: Classic or Red Dead Redemption 2. Affecting scent, noise generation, visibility, and conditions.
An active weather system that affects the player (e.g. hot weather makes you easier to smell, cold weather affects scope wobble) to make use of the clothing system.
Skills like calling or tracking having a level system. I.e. the more often you track deer the easier you see their tracks and you get a bit more information about the animal (weight estimation and gender)
A wider selection of scopes or the ability to upgrade them with better quality glass and reticles.
Rifles, shotguns, handguns and muzzleoaders having multiple calibers to choose from (3 is perfectly fine each one)
A handgun, single shot or revolvers would be great, from .22 LR up to .500 Smith and Wesson, for hunting and defense. One handgun slot is good, especially if you have to buy the holster for the handgun sizes separately.
More lever action and break action rifles, including single shots.
A regular atv and some tents to set up camp.
Even a survival aspect with food water and sleep would be nice if it was done carefully