So before I start I realised I wrote this to the devs so keep that in mind when reading. Also if you don't agree with something please tell me what part (and don't say all of it).
So I have 2 changes that I think would make Javelin a more balanced character. One is an objective buff the other is a re-work but hear me out here. So my first change is to remove the one second delay between Javelin giving ammo to players. Currently when playing in a casual match people don't tend to stand close enough to me for more than 2 or at maximum 3 seconds and in this time I gives them about a mag of ammo but that doesn't feel like your being given any ammo when you receive ammo from a Javelin. Second and the biggest change: guided mode. I think the guided mode should have a 45 second cool-down after this change. The change is a new (two second) animation where she angles her rocket launcher into the air and fires. At this point, it changes to a first person view of the rocket. In this view you can control the rockets speed, direction and height. This allows for a clear path for Javelin. As for counters: phantoms emp destroys the rocket instantly. Guardian has a clear audio cue of the charge-up regardless of Javelin’s or Guardian’s location. Also the earlier mentioned cool-down increase and long charge animation balance this out. Not to mention Javelin’s vulnerability whist guiding (You should probably make it so if Javelin is killed so is her rocket).