Anyone ever seen the overlooked 1980's Twilight Zone? I know everybody knows about It's a Good Life so having a kid with omnipotent powers is a seriously bad scenario, but what about a mentally challenged kid that can manifest objects from seeing it?
There's a great episode (co-written by George R.R. Martin) called The Toys of Caliban. It's about an elderly couple with a son in his 20's. He's mentally challenged but has a terrible power of bringing anything he sees from TV, pictures, whatever he can visualize. He can't bring living things however. He tried to bring a puppy once from TV and it ended up dead. His poor father has to bury many dead things that his son brings.
How does the X-Men deal with this? The mentally-challenged son never goes outside and his parents board up the windows as well as took away the TV and locked up books, magazines. They carefully give him picture books of inanimate objects that won't cause any harm or trouble. So you have someone with a powerful form of manifestation yet they lack the mental faculties to properly utilize it. https://www.youtube.com/watch?v=JsoUp06Cqdc
This is the 80's Twilight Zone I'm talking about
I mean, if Franklin Richards wasn't a well-adjusted kid with a strong family, he could very well end up like Anthony Fremont from It's a Good Life. A petty tyrant that can fuck over Universe 616.