When I first heard plans to make it CGI, I thought “oh shit”, Akroyd's going to destroy the franchise. The more thought I gave it, the more I began to like the idea. The monsters will look great, and since the action sequences won't be limited by actors, there's a possibility of some nail-biting action. Something i'd like to see in the upcoming flick.
On the subject of how they should do it, I say do it like Final Fantasy Advent Children. For a CG movie, it was done excellent, and had a great story to boot (im speaking of the original japanese version of corse).