Traycor
Explorer
Movies are basically a gambling game. Hence studios check off as many boxes as they can to mitigate the risk.Any D&D movie will be a gamble. Technically, any movie is a gamble between success and failure. A D&D movie can be done well, like nearly any type of movie. They could try to make it more risky with more characters to appeal to fans, when they could take the safe route with a generic plot.
License a known property that has a fanbase: check. Use known/popular characters: check. Pick known actor that has fans: check. And on and on and on. That's why lots of movies are formulaic and boring. Movies are designed and conceived to mitigate risk.