Things I noticed: No Heavies in this video. (might have missed 'em)
Using abilities takes away from a circular gauge in the bottom left corner.
Buffing yourself doesn't seem to take any more of the gauge than buffing others. Not sure about the difference in XP gain.
Medics have a longer ability gauge than the other classes, apparently.
Of course, this footage, while new to us, is from the old container city vids, so there's probably been some changes since then. More to come as I watch it a few more times!
EDIT: In the very beginning you can see that Jolly's sprinting speed was buffed. This means, obviously, that there is a sprinting speed buff. Probably a Medic thing.
Soldiers can hand out special types of ammo, like armor piercing.
Good eye on the sprint boost, to me, it looked like the soldier is able to hand out a lot of ammo for EXP as well, more than the medic managed to get from healing. at the start, he got 140 exp total for 2 kills, which is a bit more than 1 revive. I imagine those values will continue to get tweaked all the way up until release.