Basically, the big game developers that could do something like a game you're talking about...won't. Tweaking an existing genre is a lot easier than trying to start from scratch and create a unique experience. Effort must be less than or equal to the value of fiscal profit.
This is why the Wii is happily tearing down Nintendo's classic gamer reputation. They put more casual games out there (which are typically easy to make and have a much smaller development cost than, say, a Zelda game), price them around the same price as a blockbuster hit game (again, Zelda), and laugh as the money rolls in. It's a very pessimistic view, but watching commentary of Miyamoto praising the Wii as "the perfect system" and "just what he wanted it to be", I find myself believing it more and more. Also, Miyamoto has said that "while Zelda is not dead, expect it to head in a different direction". Zelda Party anyone? A mini-game Zelda would break my childhood affections to the Zelda series.
After all, gaming companies design games with a profit in mind. As long as they are getting that, as long as they can muffle the cries of gamers by stuffing wads of cash in their ears, why should they care if someone wants something cool and unique. They're too busy making generic shooter X's sequel which will somehow involve quicktime events and minigames.
And it doesn't help that most unique games fail hardcore, discouraging developers from trying a new mold.