if a game box is not interesting enough to pick up then the sales are likely to be low. At least one games studio measures this explicitly with a mock up of an actual store containing both existing and potential game titles.

Zynga does this type of testing too. They test attraction to their new ideas using a method they call 'ghetto testing': http://grattisfaction.com/2010/01/how-zynga-does-customer-development-minimum-viable-product/