I think some of the Twilight actors are too big right now to be in a television show and don't think it's the right time with Vampire Diaries and TruBlood filling the vampire genre at the moment. It's not needed right now especially since all the movies haven't come out yet. Us fan probably die for it after the movies are finished and after SM decides an official yes or no to finishing Midnight Sun.
We would all (I think) be very excited to see what Edward and Bella do in the future but also VERY interested in the relationship between Renesmee and Jacob moving forward. The conflict of not moving around to hide everyone's lack of aging because Renesmee and Jacob relationship.
Fan fiction is amazing. Some isn't great but some take you in different directions like those old books which would let choose the way you wanted the book to go with the different outcomes. I also really enjoy the older genre stories. As an older Twilighter I hated the "fade to black". After all that build up it drove me insane. So I found other stories that gave me more than that.
As for directors, no not it's going to effect the movie series moving forward but we will see in November.