The XP system obviously needs an overhaul. This is just my ideas of what to do.
The minimum they could do is just add XP upon completion of a match. 200xp for completion and 500xp for winning.
However, the ideal XP system (in my opinion) is real time xp gain. Something like 10xp per kill, 5 for an assist, spree medals would be the amount of kills times 10. At least 50xp for objective based medals. And to have all this XP added to your progression as you earn it, instead of getting it after the match. So if you disconnected while on a killing spree, you don’t lose any xp for it.