Faction reputation still exists, though at a much smaller frequency. In fo76 your reputation with raiders/settlers can affect the storyline and their reaction towards you out in the wild

Skills and faction reputation, no doubt. Karma can stay gone, but the other two are a necessity in an Fallout game.

Skills without a doubt. The TT RPG enthusiast in me craves more granular skill checks

Absent to varying degrees in F4 and 76: dialogue; skills; traits; level cap; dialogue; perk listing not artificially limited to for the sake of cutesy idea; dialogue; actually unique weapons, not just bland as far as the eye can see; sizeable arsenal (76 is getting there, even if the balancing is a joke); weapons which are not left handed for no reason, along with jamming animations; faction and settlement reputation; dialogue. Probably a few things I am forgetting.

Traits were pretty cool

Brahmin tipping should be a perk for the hell of it like read a wasteland survival guide or something

Skill points have to return none of these perks to allow you to hack terminals and pick locks. I really loved skill checks in dialog too made me feel good when I had just enough in speech to pass a check

Edit also how do you do Brahman tipping I think I remember doing it but don't remember well enough wasn't it a thing in New vegas or one of the classic games

Skills definitely. The devs should also do a thonk about the dialogue system. I have no problem with the wheel... in principle. Plenty of RPGs have done something similar well. Those RPGs have tended to lean more predefined protagonists however. The devs should therefore decide whether they want a more Shepard like protagonist (in which case the wheel should work fine), or have the traditional more open-ended character creation (in which case the older list and silent protagonist would be better).

^^ In New Vegas you can tip a Brahmin by crouching near it and interacting with it.

Ok I though I had remembered it from that game but wasn't sure