I'm sorry, but every game I've seen that is just "a collection of minigames" has been terrible. It's like, if they don't have a concept for an original Muppet game, they shouldn't make one, not just churn out some generic '80s Video Game concepts with 3D Graphics. If there was going to be a Muppet game it would have to be a well made adventure game in it's own right, with competent comedy writers for the storyline.
But you'd still face the risk of losing the inherent charm of the Muppets by having them in 3D. I mean, look at the little subtle movements of Kermit's head, just by the repositioning of a finger. As much as they'd try, they'd lose a lot of the little character tics.
It would make money for Disney, and the Muppeteers would get paid for their voice acting (which is probably less than they'd make as Muppeteers) but I'm not sure if that money would go back into helping out future Muppet Productions or whether it would just be pocketed by Disney execs, unless of course the game sold phenomenally well, but seeing as a tie-in game is more likely to be a collection of minigames, there's no way it would possibly be a high seller.
Right now with the positive promotion that the Muppets are getting, I can't help but think a poorly made game would be detrimental to the brand as a whole, as a poorly made game might reinforce the belief that The Muppets are nothing but Disney's corporate puppets.