Would love to be able to make the game feel more realistic. Big breaks of immersion for me include:
1) resource incomes from outposts (how does a fast food restaurant continue to provide daily food when not in operation?) For ultimate difficulty would like option to disable outposts altogether, meaning no supply lockers in the field, you only have what you bring with you, no areas stay permanently clear, and you need to make more trips to bring back loot which requires gas and car/survivor risk.
2) fixing cars with cosmetic/structural damage in the field (how does a little fixin' kit allow me to reattach a door and/or smooth out a hood?) Would make sense if a base has an auto shop, which would be a good way to juice up the importance of the mechanics specialization.