It seems that nearly every game-engine question is also tagged with game-development, as would be expected. Few of these questions substantively address the issue of game engines specifically, and those that do are usually in the vein of "Cryengine or UDK?"
Also, while I'm at it, is it just me or is game-development already a synonym for "Please flag me and suggest I belong on gamedev.stackexchange.com." I promise I'm not at all salty about this because a recent post of mine has been so flagged. I can see the justification. I just think it's a tough thing to say "My question should be on SO rather than Gamedev, but should be tagged game-development."
Additionally... I would like to add game-programming to this list. Since this is StackOverflow, one can presume that questions regarding game development would by necessity be related to game programming. There are only 25 questions tagged game-programming that haven't been closed. Regarding my earlier statement about game-engine, there are 117 open questions with that tag that do not include game-development, versus 177 that do, versus over 5,000 game-development questions in general.