R uses now( i think its the C4 engine I'm guessing to lazy to look it up) but like heavily modified with updated graphics and scale of the engine and so forth(including open code). Taking a map like Fallujah or another location and really making a HUGE Plantside 2 type of size map for it. Running the same type of game modes we play now INS or maybe AAS.So just think how that would be, having 1000 players on a big map so 500 each side USMC vs Insurgents or ISIS or whatever and the objective is the same find and destroy each cache and Insurgents defend but at the same time insurgents push and claim a section of the map the same way the Planetside 2 way work. lets say one USMC take a cache in a certain area they claim the section and move up from there.
Now with 1000 player servers its going to be a lot of squads so just think a platoon of like 50 LAVs over 100 inf squads, a logistics squad to run supplies a transport squad, A Mortar/Artillery Division, and platoon commander for each division and then a General Commander. Awwwwwww
Only one can dream.....
I could further explain some more but i think that's enough.
)