The biggest service they could do for the fans IMO would be to make a fun fantasy movie and show it can be done outside of adapting a novel.
I can rattle off some "fan service" I'd like to see them avoid. Please don't have it be a movie where regular people are sucked into a game Jumanji style. Please don't have the character talk about making saving throws or spell slots or refer to any game mechanics in dialogue. Please do not include a kender as a character.
(My dream would be for a D&D movie organized as if it were a heist movie rather than a high fantasy movie. Oceans 11 crossed with the Temple of Elemental Evil. Probably too much to ask for, but one can hope...)