I see much potential in this game! Here are some ideas:
1. Add cosmetics or items
By items I mean things like hats shirts and that sorts of things to Personalize een more your character. This things could be earned by doing challenges like win 3 public matches or kill 30 people.
2. Add new modes
In this point I mean thins like only snipers or squads. I think it can give more variety to the game.
3. Add more Customization in weapons
I think adding lie 3 more guns would change the playabilty of the game it could be weapons like the Groza, Scar, or Vector and add the stats
4. Training Mode
In this idea you could add a mode for training. Put a room with some things that you can find in the maps and put some dummies for the people to practice.
I am a 3D modeler and I could help if you want but ye that could help the game