A lego RPG game. With the graphics level design would come really easily, imagine a scenario builder where the player can use all blocks the developer used (and more). A solid RPG system in the style of dungeons and dragons, the online community would ensure that there's always new content. Scenario contests could be held to see who makes the best map with the winners map available online for a small fee, the winner ofcourse would be compensated
In fact screw the actual scenario made by the developers, with enough options to modify the core gameplay rules and easily create story mechanics and an abundance of building blocks to create maps there's potential for a lot of playing hours. Add in a multiplayer component and my wet dream has come out.
