What makes a theme good? There are many factors, I believe one of them is being interpretable for either a background story or mechanics. Like Summoning allows a game where we literally summon fiends to assist in the game, or a game we are a skater trying to reach the court we are summoned.

This interpretability allows both bottom-up and top-down game design. I think the reason why most recent Ludum Dare themes are like this, they satisfy both designers with bottom-up and tow-down approach.