After reading your "State of the Ghosts Address," thank you for that, by the way, I thought of something you could do to increase the immersion of the world and the authenticity or realism of the experience. I think it would be cool to have a third mode there, where missions in already-discovered territory would have a map marker, and onscreen icon when pinned, but missions in undiscovered territory (as an aside here, I think it is GOOD that land is not discovered when only passed over in a chopper) would not be marked until the location is discovered. This heavily incentivizes pure exploration of the island, and reliance on the clues you provide. As it stands, I personally don't think the collectibles system incentivizes exploring quite enough to make the time spent worth it. I'm primarily interested in Walker's journals (meat), some stuff pertaining to Skell (potatoes), and that's about it. the rest is veggies and dessert and stuff. Unless stashes guarantee good loot, which has not been my experience thus far, why bother with them? I get far more loot just doing the faction missions. It would also allow players to recon a mission area, realize they are not equipped to handle it, and come back to it later without having to rediscover the location of the mission.
You could call it Recon mode.