I think the issue with making movies is that it's really hard to separate all the different elements of story, every race has a huge history with every other race and they're all really interwoven, so it would be hard to have a movie that does justice to the necron story without incorporating the beginning of the eldar, which would then have to include Dark Eldar and Chaos Space Marines (Slaanesh
) and Daemons, which would then have to go back to the beginning with the Horus Heresy
I really do hope this movie proves my fears to be wrong, but i don't know...