Yeah, it would be nice to see Twilight's friends rescue Twilight in season 4. A common complaint about Twilight these days is that she's too overpowered, or that she's eating up all the spotlight time. Also, one of the reasons why people seem to dislike Equestria Girls is that it's really Twilight centric, and renders the other members of the Mane 6 as background characters. (I haven't seen the movie, but that's just what I've heard.)
Unfortunately, all signs point toward a Twilight centric season 4. She's just recently become a princess, and I'm sure season 4 will spend a lot of time focusing on her. It's also likely that Twilight will be the one to save the day again. Still, I'm hoping we'll get to see a lot of the other members of the Mane 6. I like your idea about Twilight getting kidnapped by an antagonist who wants her for her princess status. I can imagine Twilight's friends feeling lost at first, but remembering all the lessons they've learned together, and finding a way to rescue her.