A simple topic with a simple premis just list the top 5 things you want to see in a DLC or UPDATE.
For me
1. ammo types
reason: in NV they added a lot to the game, made strategic play more fun and allowed for even a weak weapon to shine if used with the right ammo.
problem: legendary weapons have atributes that would have to be removed for this to work (explosive, fire, radiation etc)
2. Vehicles
reason: the waste land is a big place and with the upcoming survival changes a vehicle of some sort is becoming more and more something needed. Now I am not suggesting a car. no cars would not work do to the worlds destroyed roads. I am suggesting either an motorcycle or four wheeler. Though I also think the APC's around the wastes would work.
problem: coding nightmare.
3.More weapons specificly the Chinese assault rifle and .223 pistol
reason: NA this is already going to happens well teh Chinese AR, the .223 pistol I might have to settle with mods.
4. a huge expansion to the base area
reason: fallout 4's waste land is expansive but after just 3 playthroughs I fill I have seen it all and done it all. I have played skyrim hundreds of times and characters but have only seen a fraction, but in fallout 4 I am just half way through my what 5th play through and I have pretty much done everything 2 playthroughs prier.
problem: would invalidate many mods, would require a heavy story expansion and area expansion.
5. more RP items
reason: yeah this one is a no reason item, just feel the like of variation in weapons, cloths, and armor limit RP that and many other factors which I am to lazy to list as I put most my thought into the vehicles part of this list.