Updating older maps is always a risky business.
Adding the BBs, OK
Fixing the missing/not working issues, OK
But when you start moving things around it can get tricky. We have had these maps for a while and most have their favorite and its a favorite because of small things. A base with a certain span, or bases in a certain proximity, or a layout with small bases not medium or large bases in the area that might knock the balance out of that map. One of the biggest changes of a map was when they took out Tank Town on "craterma". The new version is a ghost town. The old version had so many players in tanks that dont normally drive tanks. You could survive long enough to learn a trick or two, maybe even get a kill or two before you died only because there were just so many targets! That update destroyed the best part of that map.
Minor tweaks seem to work out well. Kenai's update on "ndisles" I think works well. Did it mess with the tank town on the big island? I dont know, never spent much time there. It never had the same popularity as the crater map TT.
Personally I would rather see new maps. The guys building the maps are getting pretty good at making maps that seem to almost force action in areas. Also, new means you have to "find" your way around and learn the layout making it more of a challenge.
I agree that the tree count should be "cut down" <--- see what I did there

Curious would adding a destructible vehicle hanger on the edge of towns associated to a field be destabilizing to the game play.
I dont think you can as the hangers are part of the tile they are on and not separate objects.