Quoted from pinballcorpse:

I disagree here. I think kids are making a nice comeback into pinball playing thanks to us adults with our home collections. We also help spread the word by taking the kids to shows and tourneys. Our kids show/invite their friends and so on.
The themes Stern picks helps a lot. TF, IM, X-Men, S-M, BDK, Tron all appeal to kids. Even AC/DC is popular among the kids.
I think adult themes are 100% NOT the way to go. While I like horror, violence, zombies, guns, blowing stuff up, beautiful women etc., I appreciate that is not good for the future of our hobby and the next wave of younger pinball players.
The theme does not need to be toddler/preschool based, but if aimed at pre-teens and young teens, that is the ticket. There is a good chance the pinball-collector parents will like it as well and since they are the ones buying it, it is win-win.
I think Hot Wheels would be a great theme for Stern.