In this podcast for Kotaku, Sven Vincke and company confirmed the wish spell but also stated that some spells were banned. They use a three-color-coded list of spells. Green is good to go! like magic missile. Red is "never gonna happen". He didn´t enter into specifics but they said that is High-level stuff. . 38.15
Wish is accepted because it has a role in storytelling, so It seems wish would be in the game. Casters would not be able to cast it because of the level cap but maybe you can find scrolls, items like the djinni lamp or something like that
https://art19.com/shows/kotaku-splitscreen/episodes/1f188c51-4594-42d9-a255-7d2f528ad8bc
