There should not be such a low cap for XP you can earn per match. If I go 45 and 15 in BTB heavies I should be able to get more XP compared to when I go 15 and 35 in the same game mode. When I went 45 and 15 I got 2,300 XP for completion, 8,000 XP for performance, and 500 XP for teamwork. When I went 15 and 35 I got 2,300 for completion, 8,000 XP for performance, and 1,000 XP for teamwork (more assists). There should be no hard cap for the XP earned per match. Also the linear progression of unlocks is less than ideal. You should be able to spend the token you earn for leveling up your rank on anything you want, the more "elite' or "pristine" items in the list should cost more tokens than the less desirable ones. This sort of leveling and unlock system is the reason there are so many bot and AFK players in all the lobbies.
Those are my two cents about multiplayer.
Oh also campaign should count towards leveling up your season pass.