Wow, Ben took the words right outa my mouth.
Part of the enjoyability of Mario games is actually the nostalgia of Mario himself. So while I definitely think these games get more consideration than the exact same game without Mario or Mario themes there are some good reasons for it.
The important thing to note for me is that Mario being in a game makes the game more fun if for no other reason than the nostalgia. But the standard of quality Nintendo sets forth for all of its games, especially Mario games is something they quickly and easily convey to consumers simply by putting "Mario" on the box.
And that is what mascots are for really. Building your brand image because people can associate a vast amount of feelings, information, and memories to a brand and you can make them associate all of that to your game with your brand label. So Mario is most certainly a well built marketing tool, but I don't think that takes away from the fact that it had to be good in the first place to build that sort of instant brand recognition. And I don't think brand loyalty is guaranteed once built up, I think it must be maintained. And Mario does that.
Anyways, enough rambling on, I'm sure you get my point...








