To make a great game? Layout / shots / code. To make a profit ? Theme.

Time and time again it is proven out that theme surpasses the actual gameplay - Take Stern - they are reusing layouts, throwing games together quickly, and getting them out the door. and they SELL! The thing is, they're all fine games. Each release may not be the greatest of all time, but they're solid enough.

Then look at JJP - they released a game with one of the greatest and fun layouts of ALL time, with extremely mature code at release - called it Dialed In... and half the market didn't buy the game because they "couldn't get into the theme." It boggles the mind. Iron Maiden is a Stern example of the same phenomenon - "I just don't like the music..." despite the inspired design and innovative rules.