Glory to Arstotzka! Hehe. When I thought about it, the permadeath came to mind. People whined about it in Diablo, but is was optional. And with all the rogue likes, the concept is almost a sign of a good game concept now. So yeah, bad game concepts are hard to think of. It might be, that it is always just bad execution. The other ones were of course the Larry games and the whole genre of visual novels.
I am sure many known good game concepts could be pitched in a way that they sound boring, nonsensical or just like a bad idea in general.
There are just too many existing games that do well, but are not appealing as a game concept to many. Kinetic novels for instance. Even if I would like the story, it just would not be a game to me. As soon as you have any type of input that the player can optimize, the gaming part starts. That is one reason to play a game, but there are many more.
You cannot even pitch a bad concept like: let's make a game about x, but the graphics are bad. Because, already done and working, see pixelart games and of course Minecraft. Some people even made a fighting game ... with only on button. I believe that is even a genre now.