What is your top nerd fantasy? What game, adaptation, or other thing would tick all of your boxes?
For me it would be a big budget, Game of Thrones-style adaptation of the WH40K universe, covering everything up to and including the Horus Heresy.
Season 1: Birth of the Emperor after all the shamans of the world commit suicide, going through history to the Dark Age of Technology to the Age of Strife (only later on, maybe in Season 2 or something would it be revealed to be the birth of Slaanesh), his defeat of the techno-barbarians (all this could probably fit into an episode or two, max). The creation of the Primarchs and their scattering. Introduce the Ruinous Powers. The Great Crusade, the building of the Imperium, and the Age of Reason. Introduce Eldar (Alderi or whatever the hell they’re called now), the Orks, and Tau. Season ends with the first signs of trouble brewing with Horus and Magnus the Red being tempted by Chaos.
Season 2: Many adventures and battles as the Great Crusade continues. Learn more about the Chaos gods, Eldar lore, introduce the Necrons, and maybe even a bit about the war between the Necrontyr and the Old Ones? The Tyranids make their debut, a few Starship Troopers-type episodes would be awesome. All the while, the seeds of the Horus Heresy are growing and the season ends with Horus turning to Chaos.
Season 3: The Horus Heresy. Daemon Princes, Greater Daemons, converted Nurgle teams, Chaos Marines, the works. Huge battles, the Battle of Terra, everything. Series ends with the battle on the Vengeful Spirit, and the ascension of the Emperor to the Golden Throne.