look i think a fallout rts would work..but you have to scavenger resources. so u send out prospectors/scavengers to hospitals for meds, to military bases for weapons..which u can sell or give to troops. you ocupy buldings that already existed or when you become more advanced you can build smaller buildings.
different troops may be an issue for some factions. ncr have no issu. trooper, 1st recon, rangers, veteran ranger (which maybe only hapens after they kill a certain amount of people like C&C Generals), heavy trooper etc. but bos..u have inciate, knight and paladin....like in eBOS u have lyons pride but ther don't have anywhere near as many as NCR or Ceasers legion.
i agree with sebor tho.. has to be done after FO4 so we get the aditional factions or faction chapters.
but i like the idea alot..i'd put myself down for several collectors editon..and if they had any dlc stuff come out with i'd get that as well....so bethesda if you're seeing this...u got several hundred from just me if you do it hahah.
anyway... i like the idea of each faction having pros and cons...and there could be several campaigns. from fallout lore and canon. so the NCR vs wBOS, enclave vs NCR, Unity VS bos (and everyone else), NCR vs khans and vipers), eBOS vs Eastern Enclave, NCR vs Enclave, battle of anchorage etc. have little campaigns that are canon then have skirmish..which is there just for fun..and has no relevance.
but you alos have like smaller factions which u can recruit like the natives on AOE3.....it could work....and i could keep going..but i'm procrastinating enough as is