This is my first post so.....
Have it set around 2017-18 in some middle eastern country (counter terrorism) ,south america (stop drug trafficing by assasinating drug lords) or maybe Darfour (bring peace). Try to end the game to where it flows into the events of END WAR.
DO NOT HAVE A COVER SYSTEM. it makes the game feel more like an arcade game
do not rely as much on gadgets
have more open world maps (forest/desert) as well as urban maps
lean feature instead of cover
do not have imaginary weapons (MRC) stick with SCAR, M16a4, Etc.
10v10 or 8v8 with random AI
maybe even have "hot spots" that are around the world that your team can drop into and play against AI or players..........
In conclusion that is what a want in a sequel to ghost recon.