I think SOGPF is a near perfect rendition of the Vietnam war experience in ARMA. I think the gear and guns currently in it are good to go, and nothing else needs to be added in that department. The biggest items on my wishlist would be for for several key vehicles which are currently missing. I know some of these are currently in Unsung, so perhaps they could be fixed up a bit to DLC standards and ported it over? Some would need to be completely re-done I think.
M113 APC (multiple variants)
M706 Cadillac Commando
M551 Sheridan Tank
US PBR Boat (Patrol Boat, River)
O-1 Bird Dog
F-100 Super Sabre
Mig-17 or Mig-21
Ch-53 Super Stallion
HH-3 Jolly Green Giant
I think the addition of a rescue hoist, and some kind of stabo deployment system would be nice to have as well.
The US Embassy in Saigon - I think bit of an oversight to not include a custom one since it's such a historic building.