Actually "New Coke" did fail because of taste. When New Coke was "enginered" it was tested for marketability by with "sip tests" (i.e. people taking a sip of the drink and comparing it to other versions). "New Coke" was sweeter than "Original Coke", therefore more people prefered it to the other candidates when taking sip tests. But when "New Coke" was relesed and people drank the stuff for real the taste was too sweet to bare.