My dream game would probably be like this down here.
Let's see some characteristics from these games:
Grand Theft Auto 5. Ragdoll physics, a lot of stuff to do, big open-world map (not SO big, but still...) and you've got 3 characters to play with.
The ragdolls - I'd spend hours pushing people just to see how they tumble down a mountain, lol. Poor NPCs.
More than 1 character to control - I don't know, this seems like Lego Star Wars all over again...
Next up: Crysis
You can pick up turtles, boxes, crates, barrels, grab people and throw them.
And, the thing which makes it not a generic shooter is the nano suit. It's cool.
Getting a nano suit equivalent (in my dream game) during a level in the second half of the campaign could be thought of. After finishing that mission, the nano suit can be left in a closet or something, and could also be re-used later.
And, of course, I'd love to experience mapping for the game. I'm a mapper and I'd gladly map for that game.
Then, something with a nice addon system + the Workshop integration (a good example of this is GMod) wouldn't hurt either.
Also, a good deal would be having a singleplayer campaign, and a multiplayer with co-op missions included (as well as being able to create co-op maps).
Now, the game's genre would be along the lines of first-person shooters. I'm saying that because it wouldn't be a 100% shooter game. Hmm, maybe something like a mix of GTA and GMod but without the crime, the adult content, the Physgun and the Tool Gun.
Regarding adult content I meant sexualised stuff etc.
I'm fine with violence, lol.
Now, the character design. I'd love to see furries co-existing with humans there, haha. Don't call me a furry, I just like the concept of anthropomorphic animals and maybe a few more things about them.
And the story would be set in the near future (10 to 20 years from now).
Also, since the furries would be there, an alternate history to it would have a purpose.
Valve's way of telling stories would also be nice instead of cutscenes.
So, that's how I imagine my dream game. I might have left out some things but I think that this is enough info.