I think the icon range is fine. The thing I wish HTC would chance is the identifier range. For instance, at 6000 yards an enemy icon would show an enemy icon of either 4, 2, or 1 indicating the number of engines a plane has. Then at 3000 yards have the MODEL show up (109, P47, A6M, etc), then at 600 yards allow for the type (109G-2, P47M, A6M3).
I think the 6000 yard identifier icon is a bit much, I think there should be some more "fog of war" immersion and this would help provide that. Currently, anything beyond 6000 yards is seen as a dot and before it is in icon range we can simply look at the map ans see if there is a friendly in the area and if the map is blank then it is obviously an enemy. Once that dot becomes a red icon showing that it is a Nik2, it allows the faster planes to tuck their tail and run MUCH easier than if the identifier simply said "1".
I think it would actually encourage more combat. Icons give too much away too soon.