I've got mixed feelings about 3d spotting.
On the one hand, it's nice when you're out there, no one is visible and yet you're still getting targets to shoot at. As cheesy as it is, there is some gratification to be had in snapping off some rounds at a triangle and getting a kill you didn't expect to.
But on the other, that's why it sucks. You'll be running along and ~ZIP~ you take MG36 rounds from the other side of the map because a medic is just camped out shooting at triangles until they start scoring hits.
IMO it would be a lot better if it was more range sensitive. If triangles came in and went out of view depending on your distance, your scope, your class.....something that keeps the advantages of spotting (coordinating attacks on people) while ditching some of the cheesiness (just shooting at triangles all day.)
Sadly, 3d spotting seems ripped straight from BC2. So it doesn't look like it's gotten anymore advanced. Oh and now your squad leader is identified by their own individual spotting mark....so expect that when you're spotted as a squad leader, the whole enemy teams turns to fire on your bright orange star.