From what I heard they got rid of the XP popping up instead they have a counter that will appear under your cross hair and it will total up all XP you are getting I.E like if you are carrying something to a base it will total up all XP you get from that and other things like killing.
Correct and an official dev statement.
If I remeber the gameplay video directly they had a translucent circle kinda thing around your already circular crosshairs that filled up as you killed an enemy or completed an objective, quite cool, easily seen, and unobtrusive IMO. I mean you'll already know how much exp you've got and how close to completing a task you are all while looking at the same place you would have been anyway.