I haven't played mafia in about a year or so, mostly because of school work. I'd be willing to start playing over the summer, though.
i think one reason why interest is starting to fade is that games often ending up being the village leader telling everyone what to do, and a couple people in the mafia telling everyone what to do. While it may be the form most conducive to victory, its pretty boring for everyone else. The games in which everyone is forced to participate (the last game I played was the card game, every man for himself one, the name I have since forgotten) are usually expert games, meaning people who weren't experienced or confident enough to be leaders were stuck in a cycle of playing normal mafia, getting bored, and not getting into the interesting ones.
So while the distinctive style of smogon mafia (2m1v, village leader) is declining, I think that is because of the inherit flaws in the format, namely making it interesting to all parties. That being said, normal NOC mafias are pretty terrible too imo, so while I can't suggest anything specific, I think we need to look at why interest is decreasing before we look at how to increase it again, and solve the underlying problems first.
1985, before the Iowa-Michigan game, Coach Fry sent a guard out to long snap during pregame punting warmups just to mess with Schembechler, then turned his back while the guard wildly snapped the ball over the punter's head, off the turf, and into the second row. Schembechler, watching the display, asked Fry, "You're not going to let that guy long snap today, are you?" Fry responded, "Coach Schembechler, I don't plan on punting." Go Hawkeyes