I want Bethesda to do an open world Sci-Fi.  Not Post-Apocalyptic like FALLOUT 3.  But Sci-Fi like Star Wars.  I want different areas to have different experiences... kinda like Half Life 2 had.  But totally open world, rich and detailed like Skyrim.  With the crafting, but without the incessant Loading Screens. 
I want more weapons like Boardlands 2.
I want more vehicles like a GTA.  But Sci-Fi.   I want cars and trucks and bikes.  I want aircraft.  I want spaceships.  I want ships that can get from the surface (and land anywhere) to orbit.  I want ships that can go from one planet to another.  From one Solar System to another.  I want a ship like the Firefly that can carry other ships or vehicles in it. Ships that require some crew - I want to be able to hire those crew... Like Mass Effect, but with more crew.  Crews and Teams.

Not like some Steam Punked HG Wells Sci-Fi... I want a big Space Opera Sci-Fi.  And when I say Open World, I want more than one World too.  And not every World be like 1 City.  I want WORLDS.  Super Planets, Rings, Dyson Spheres,  Binary systems, Clusters, Asteroid Belts.   I want Alien Species.  Alien flora and fauna.  Alien Creatures.  Alien Artifacts.  Alien Ruins.  Alien History.  Alien Technology that can be used and combined.  All that s___.  With planetary seasons and weather represented on each planet.   
I want it to be absolutely staggeringly huge.
And I want thousands and thousands of stories you can be part of.
I want it SINGLE PLAYER like Skyrim - with the ability to Multiplayer with Friends and MMO when you want to.  But mainly - Single Player.   
Maybe make each Star System it's own DLC, but each DLC be just freaking huge.  Every DLC be like a whole new Skyrim, not just special areas and quests. 

This is what I want in a game.

Sounds kind of like Elite: Dangerous, though I don't know if that has much on planetary surfaces.  From what I've seen, it looks like it's mostly spaceflight stuff.

I think you guys are missing the little Detail that I want Bethesda to do it.  Reason, because Bethesda doesn't suck.
No one does world building better.

Who did the Mass Effect series?

Bioware

All the wonderfulness confused it for me.

Bethesda makes the world, Bioware makes the people and lore.

Who are you, Jacques Cousteau?

Maybe he wants the opportunity to play Admiral Ackbar's childhood.

Or to conquer Mon Cal.

I would love an open world Sci-fi game. Make the next Mass Effect open world and you'd have a great starting off point.

Mass effect had the same problem that the KOTOR games had, it is an RPG masquerading as a shooter. Clunky doesn't beging to describe games that look like they were tailor made for me, and wound up being too painful to play. (Yes I know both were critically and fan acclaimed, both made by bioware (who do make good games) but I couldn't force myself to like any of them) The borderlands games did a much better job of hiding the fact that it was a Diabloesque Loot gathering expedition, by making it fun.

George the game you are describing is a Unicorn... I want it so much I could scream. Shooting for the shooters, Vehicles for the drivers, ships and planes for the fliers. Worlds to explore, tech to exploit.
But as a single player masterpiece... it is highly unlikely. The budget for something like that could only come from the money printing machine that is an MMO.

But we can dream right?

I wasn't talking about the mechanics of Mass Effect, but of the world and characters. Use that with a Skyrim, Fallout type engine. But yes, add customizable space ships.