Sora
His epic search for Kairi, along with the gift of the Keyblade, has transformed Sora from a naive little kid on the island to a young man who has seen all kinds of evil in all sorts of worlds. The multiversal battle against the Heartless and Nobodies has given Sora a chance to crossover into different Disney worlds, so he’s had plenty of practice for being the next Doctor.
Simon Belmont
Anyone who has spent centuries fighting Dracula and millions of other demons and vampires and monsters deserves a nod to audition as the next Doctor. Simon Belmont’s classic good versus evil battle has spanned eons, much like the Doctor. He might be a departure of the beta-male gentleness common in the Doctors passed, but his brute desire to right the world would be refreshing and pretty badass.
Ness
When a meteor falls a few minutes from your backyard and weird monsters start invading your town, you have to step up and be the hero. Ness grabbed his baseball bat, collected a few friends, and discovered his PSI powers. He fought one of the greatest evils in Giygas and beat him with love, faith, and prayer. He’s a great fit to be the next Doctor, although he might need to age a few more years.