We recently did an interview with Planet Half-life. You can see it here.
Chief-Phillips: Are there any special features you plan on adding to further releases of Battlegrounds? If so, share them!
Draco: Oh, we have plenty to add later. Our current focus is on getting everything that makes bg what it is into the source game, then the improvements come. Some we have are secondary objectives, like opening alternate routes or getting a better spawn area. Also there's a morale system we are considering where capturing a flag gives that team a very short boost in certain abilities. The community seems to think we need more classes, so there are also plans to let the mapper edit the classes, like different models and sounds, as well as team name.
Black Panther: I am personally considering and experimenting with user controllable ships and other kinda of vehicles like carriages or horses. If or how these will find their way into the game only time will show. These ideas still need time to be refined and tested.