So we could put Terminator, Alien, Predator, and Blade Runner in the same verse? How would that work out?????
Predator would be easy to place in the Universe since it takes place earlier then the other settings. With
Terminator, the time travel shenanigans seem to keep pushing Skynet and Judgment Day back. The other ironic thing is that
Terminator could work as a post-post apocalypse since the world
after Skynet is so rarely touched upon in regards to what would Earth turn out like if they just destroyed Skynet's Central Command and there were no Time Travel shenanigans (or it was some sort of multiple timeline thing going on so the timestream just keeps chugging along regardless).
And of course there's always the idea that even if shut down, Skynet could be squirreled away somewhere else, it is a computer program after all at its core.
The problem with adding
Blade Runner into the mix is that it's pretty staked out on timelines. You could add
Blade Runner but it'd be an alternative verse type of idea (so another literal crossover as the OP says) which is perfectly fine. But at its core it'd be a Blade Runner AU as opposed to the actual film universe as is. So you'd keep the megacorporations and replicants and other themes and characters/organizations to flavor up the new crossover setting.
Another thing is that
Blade Runner is linked to other settings as well, most famously the movie
Soldier starring Kurt Russell where the Battle of Tannhauser Gate and Shoulders of Orion is mentioned. The character in
Soldier is also qualified in the use of the M56 SmartGun and the M41A Pulse Rifle, which obviously are from the film
Aliens and the Mark IV BFG from classic
Doom. The main writer of
Soldier was a co-writer on
Blade Runner.
The art designers and writers on Soldier had so much fun on
Soldier tossing in Easter Eggs, you can see half of Kurt Russell's previous films were referenced as well as everything from weapons used by Marvin the Martian of Bugs Bunny fame to seeing bits of the
Lewis & Clark (of
Event Horizon) laying about the surface of the garbage planet (which obviously means
Event Horizon and therefore Warhammer 40K is a tie in as well
). But on a more thematic level, one of the awards Kurt Russell's character is given is the 'O'Neill Ring Award' which is a reference to Kurt Russell's role as Colonel Jack O'Neill on
Stargate.
Is your mind spinning yet?