In general Games Workshop has been greedy and petty in welcoming good use of their license, and Blizzard more or less stole everything from Warhammer Fantasy for Warcraft, and anything from 40K for Starcraft, before either had chance to have real mainstream exposition, and now kids think Warhammer is copying Blizzard.
But Games Workshop blocks most everything so really nothing gets done, it's only been a few years since the one and only 40K movie was released, Ultramarines, which was passable but could and should've been so much better, and the games have in my opinion been pretty bad since Shadow of the Horned Rat and Dark Omen, until DoW, which is good but also could've been much better (more like Men of War and less like Starcraft, I mean there's lots of micromanagement but very little advanced tactics which even dominates the tabletop original). Also fan-made stuff are constantly blocked, for example the guy reading 40K books aloud on Youtube etc. any attempts at making fan fiction, animated movies (though seems Lord Inquisitor has gotten a green light after much unnecessary fuss and debacle) and so on.
The only thing they've been good at releasing are books and the original table top gaming, which really is ridiculously expensive since new rulebooks come out all the time and after armies started being less uniform to facilitate a higher price tag. Original Warhammer by necessity only being a hobby for spoiled kids or adult nerds, until the new generation of video games and books, where you can be a Warhammer nerd even without playing the tabletop game.
They have some of the coolest design and greatest lore, but it is seriously squandered for some reason (probably exorbitant license fees), the whole Blizzard surge could've been in the Warhammer universe, and the game industry better off for it.
