As for the game mechanics, I would imagine that the low frequency of visits really was the major factor in the apathy towards them. Our startup (IActionable) is creating a game-mechanics as a service system and one thing we noticed is that it's only really useful when employed on a site that users typically visit fairly frequently (like once a week or better, ideally). There are other factors too - like number of integration points - or how many things can a user do on your site. The "game" is hard to make interesting if the user can only do one or two things since there isn't a whole lot of interesting stuff you can do around that usually.
