If I were to do it, I'd keep the same actors (Ian Holm is I am afraid much too old... my first pick would be Martin Freeman... and get him to learn how to act as Ian as Bilbo as much as possible), keep it with the same visual universe as the films, not screw up and hollywoodify the story (just break down the hobbit storyline to a more fit-for-film version.. like eliminating Beorn but keeping him for the Extended Edition), and get as much of the crewmembers from it's precursor as possible.
Those things should be top-priority for any stupid director (out in hollyweird right now) who would try to do The Hobbit. Hell, just get me to do it!
