I agree with most of your post and suggested them before for the airborn company, but the problem with the plane is that it's a giant giveaway as to what you will do and that you currently have a unit infiltrating (which you probably don't whant them to know).
For the realistic part, you could see it as them being dropped close to the drop zone (just outside the map) and the zone they whant to pin point is on the map.
That's how i'd see it, because i'd hate to tell my enemy with bells and whistles that i am airborn and currently iniltrating a unit.
Well, the other "infiltration" would be to allow them to infiltrate directly into buildings, which is not going to work because they can hop out and drop arty immediately. Spawning from any side of the map is an interesting idea though, that would be nice to see for a pretty high opportunity cost.