I am a fan of your game and i think DirtyBomb has great potencial. I know you are busy fellas but i wanted to share my ideas for your game. Long story short:
1. You could chage the markings of objectives from label on top to conture of it, and make it see throu walls but only of repairable targets like EV.
2. Your tutorial needs reworking, you should add a sequence with an engineer repairing an EV or smth. This will make tutorial whole: shooter with throwables, medic, engineer all shown.
3. Adding the Headhunter. Headhunter is a training program, like in CS GO practice maps. DB is a fast game and requires intense body tracking. Player will have to follow some sort of a movinng target shooting witch will provide points, extra points for headshots. It will help new players be better in the game and will provide advanced players some variety to Assault Course.
Make it for individual gun, with mastery levels, cobalt mastery will give some unique weapon skin for that weapon only.
4. The thing you must do ASAP is variety in the game modes. As Objective and Stopwatch are basically the same and becoming monotonous. Deathmach should be your first step but not the last.
5. Give players ability to create modded maps i know you are independant so to make your fanbase work for you is beneficial. Also you will know what the game needs, and what players want, helping for game to grow.
6. Add some backstory for CDA and Jackal, it will add flavor to the game. I personally find story interesting even if it is not obvious. Maybe make a short cutscene at the beginnning of the game to make players look for the hints of who the real bad guy is (i personally think they both are bad)or leave the minor hints through the game.
I know its alot, you may had some in mind already. Hope this helps. You can plan, but at he end it may become something completley different. Sometimes you must give your project to swim by the current freely a little bit to reveal its true potencial. Sorry for bad English. Sencerely Achilles