Engine-
What everyone would like to see in the next fallout game is a new engine, one that is preferably far better then skyrim's creation engine (giving us, the gamers, a ultimate fallout experience).
To go into a little detail the new engines graphics should see more color put into them, more 'shine' just because we're in the post apocalyptic wasteland doesn't mean we can't have new weapons being built, polished, ect. A new third person perspective like seen in The Elder Scrolls V: Skyrim ect.

Races.

-Android.
Just like Fallout 3's Harkness.

-Ghouls.
We all know what a Ghoul is so there is no need for a description.

-Bethesda original idea?
A Bethesda original idea, knowing Bethesda they could bring us a totally new unique race to play as.

Map, General Location.
-The map should be at least two times Fallout 3's map and every dungeon should be unique (like in skyrim where no dungeon was the same).
-Fallout 4 should be set in a big location say New York City, San Francisco (again), or even take Fallout to a location in Germany.
-Yes Fallout is set in a post apocalyptic wasteland but that doesn't mean we can have populated cities, actual cities not small areas filled with meaningless npc's (as seen in Fallout New Vegas) were there could be more interactive npc's.

Stroyline.
-The storyline should be unique and go into quite a lot of depth, way more depth then Fallout New Vegas so it gets that true Fallout feeling because face it Fallout New Vegas didn't feel like a real Fallout game, t'was still a awesome game and gave me reasons to have quite a few playthroughs but we want a true successor to Fallout 3.