Looks like Worlds of Fun has already started teasing their 2017 addition. I remember reading a while ago that they'd probably be receiving two vintage flat rides next year, but I don't think they'd be teasing this early if that was all they were adding. My guess is that it could be a Triotech dark ride, or maybe a medium-sized coaster like a Tempesto/Phobia clone, which would be a perfect fit since WOF doesn't have a launched coaster. Probably wouldn't be a $20+ million B&M since that might be a bit too expensive for a park of this size.