Please do no combine tedium with combat improvements without the option to access combat improvements separately.
I will always play on survival just for the slower healing, and will definitely want more realistic damage if they do pull that off with the update, but I do not want a bunch of annoying other junk tied to the only difficulty that makes combat remotely challenging.
Saving only on sleep is not fun and players can get this experience separately easily. I like "Ironman" playthroughs but I never use the save enforcing features in games with substantial technical issues that can ruin a save - which is true of Fallout 4.
Needing to eat/drink also needs to be separate if added. It will be tedium only, because food/water are easily made and stocked up on. It's not adding anything substantial to the gameplay.
Last but definitely not least, no-fast travel also needs to be separately toggled. You designed this game to send players around the map with no concern for on-foot travel time. That should really be enough said. It's also currently super easy to avoid/escape unwanted combat while traveling, so it really just is a bunch of extra running/walking, not a significant survival challenge.
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I understand some players will enjoy some of the above features even if they're not well integrated into a game not designed for them in the first place, but it's easy enough to just add an extra option for players who want only the more realistic/difficult combat without the tacked on survival game features.
Ideal solution would simply be an extra little checklist for survival, where you check the boxes for the features you want and leave those you don't empty.