Since the beginning of the ArmA (ofp) series it's been quite annoying and still is when it comes to trying to place objects with precision. It's impossible.
Especially if the object-icons are huge intersecting squares with a "[B]?[/B]".

It has not been to big of a deal before, but A3 loads the island(s) slower, resulting in object-placing being quite time-consuming if you want to preview your changes.
The next best thing to a 3D editor would be to actually have the object-icons properly displayed in a 1.1 scale to the object placed on the map.

If the icons were in a scale that is correctly representing the size of the object, things would go 10x times as fast.

Icons could as suggested be the object rendered in "wireframe" when you zoom all the way in, but still just be icons.

That would give all an exact representation of the objects positions and shapes. There would be absolutely no impact on performance and it'd help everyone greatly.