You just never know what will catch on. I don't see what the big deal is with Angry birds, Candy Crush or that awful-looking mindcraft game... but here I sit, very wrong about my predictions and not having tens of thousands flowing into my bank account every month.
I think what the public wants is something that's easy to pick up, addictive and naturally fits into their daily routine.
Maybe I should just go make this game - http://www.youtube.com/watch?v=is12anYx2Qs