You know what video game I want? I want a video game where you can be or combat The Thing (John Carpenter version). Not the really, REALLY bad games that make no sense and have been christened 'Piss, Vomit and Panels', but something that's actually GOOD and stuff. It'd be like Spore but infinitely more complex and badass. It would be a pain in the ass to change out of th blue without having to design every 5 seconds, but maybe you could design a bunch of limbs/bodies/etc and then pull them up in a tab ingame (the game would pause as you do this), put the part that YOU desgined on wherever you needed it on the Thing, and unpause, watch it transform, and proceed to wreck shit. Hell, you could even build spacecraft if you went far enough! It would be an absolute bitch to do, though, because to do it right you'd need DF levels of procedural generation and attention to detail, combined with at least moderate graphics so we can see how the wings we put on our curent form flap as we fly, or the way people spasm as you impale them on the end of your giant spike thing growing out of your arm.
If anyone ends up making that, I will do great things for that person. Great things.