I had a few ideas (and had a chat on TS with a few people) about incorporating the FOB into side missions.
2 examples would be a full fledged defend of the FOB, where there could be a timer until the attack starts and then it's on. Another example could be "An AT team has positioned itself overlooking the FOB to take out anyone leaving with a vehicle, search the area, take them out and destroy their missile cache"
I figure it could give the FOB a bit more purpose.