Here are a few minor things that I think the vanilla build of Arma 3 would benefit from

-Low tech artillery and AAA armor (or static) assets for the AAF

-IR Chemlights

-Inability to reload belt-fed weapons while moving

-Ability to view the GPS in tanks, IFVs, etc… while in first person

-Ability to “track up” the GPS (i.e. orient the GPS map to your direction of movement)

-Heavy Gunner, Sharpshooter and Recon classes for the AAF

-Add faction MRAPs with a HMG/GMG combination turret like the UGV-RCWS or Panther IFV