Here be Wisdom
David Lancaster of Rebel Planet Creations made a couple of videos on game design in 2009 and uploaded them to YouTube. I don’t know the man so I’m not sure what HE would call them, but I’d describe them as short informal video essays on the subject.
Essentially his message is: focus on the gameplay. Set everything else aside. Don’t worry about theme, don’t worry about setting, forget about fancy graphics or elaborate sound. Make fun gameplay and a great game is more likely to follow.
I think quite a few turn based combat designers could stand to give these a watch or three:
I don’t want to put words in his mouth so get it from the man himself: