To my mind 'HUGE' means a big change to the game.
A camera just wouldn't cut it ( although I would like to see a camera mode in the huntermate, like COTW), and zeroing and sighting of rifles seems a waste considering the limited render distance. Could be something like the revival of in-game chat, or personal bests, but I don't see how they could monetise that effectively.
To me a huge change would be:
Animal AI - Complete redoing of the animal AI, so that they actually interact with other animals and the environment. Changing the way they are called, react to shots, actions when injured, predators hunting prey, fawns and babies with females, actual hunting trails, etc. Probably wouldn't require new gear tho.....
Trees - Make trees great again! allow birds to land in them, and smaller critters to make them their homes. Opens up new animals and possibly smaller firearms or slingshots etc.
Night hunting - introducing nocturnal species? Could open some revenue possibilities with new equipment.
Fishing - I'd rather see a deep sea style fishing than a stand and throw a line in a pond style, but either way.
Africa - maybe this is a fancy new reserve announcement? I know Alena said that Africa was probably never gonna happen due to the controversy of hunting the endangered species. They could simply not have them in the reserve, plenty of game in Africa without them...... or ....... what about an Africa reserve that features the big 5 that doesn't allow actual hunting but requires the player to get photos of the species - Attenborough style? That might satisfy the camera aficionados and those who want an Africa map.
Guilds - A long requested feature. Sure to please a lot of players.
The Joining of the reserves - joining reserves up so you can walk from one to the other? Don't know if it has ever been requested before.
A New Engine - forget extending render distance, how about just going to the COTW engine and being done with it? I know this gets a big controversy every time it gets raised, by people who wont be able to run the game because of obsolete equipment. But how long can EW keep this engine running? Unfortunately gaming is one of those hobbies that requires a constant state of upgrading in order to keep being able to enjoy modern games.
Transport - Horses, Bikes, Quads, ATVs. Don't really think the reserves are large enough to require them, and may make multiplayer a bit of a headache for some.
Just some thoughts. Apologies for the length.