As much as I love Contra, I don't think it really works nowadays. I mean, look at Contra 4 on the DS. That was a good game, but one that I didn't really care to play after 15 minutes. The things that define Contra --its style, difficulty etc-- appeal to a very niche audience, I believe. The only way they'd be able to create something interestng out of the series is to go to extremes and redo it, but that would displease fervent fans. In the end, I don't think there's anything you can do with the franchise but to let it sleep and be nostalgicaly remembered.