There are some mods I would recommend if I remembered what they were... that increase the difficulty in better ways than what "very hard" does which (iirc) is a flat 1/6th damage going out and 6x damage coming in. Survival mods that make wandering out in the wastelands without the proper supplies an actual dangerous thing to do.

Something I never understood is why NPCs don't have immunities to certain weapon/ammo types. Give me a reason to carry an energy weapon, or an explosive weapon, or something that lights guys on fire...

I guess "reason" is something I find lacking in these games after the first few hours. There is hardly loot to find, forget about useful loot... a lot of the same item dropping over and over again... the difference in armor types is basically just a DT number...

Random encounters would be great, something resembling a boss or larger scale fight along the way would do wonders for the progression in these games. The wild wasteland things to find were a nice touch, something like that seems to have been completely lost in Skyrim though.

They maybe just need a bit more structure and limitation in the character design... something that could actually force you into certain play-styles. Sure, everyone starts out their character in these games with things like that in mind... a melee build or a sneak build, trying to be passive and not kill every living creature... whatever your heart desires... there are lots of "choices", just not lots of effective choices. Things quickly devolve to the point where if you are not ready to deal with slowing down enemies and/or shooting them from a distance, you are just going to get surrounded and beat down.

What I had suggested earlier, that they need to unlock different AI packages as the game progresses (or you play on harder difficulties)... would do a lot to change up the tactics of combat and give the game a better feel of a change in power or progression... without it the games are just extremely repetitive.