There's a lot of good games out there, but there are so many things I wish gaming companies would make that haven't been done
Now when I say "dream game," I don't mean unrealistic, super expensive, futuristic games that have everything to your specifications. I mean games that can actually happen that you would love to see, but haven't and probably won't.
For me those games are one's like
Battlefront III - which almost happened, but didn't,
Some more updated sequel to Spore with better functionality and multiplayer,
Super Smash Bros. 4,
Some in depth, up to date RPG that is still kept G-rated and lacks 'spells' and such