Has Neca said there was licensing issues? They're usually pretty quick to answer things like that (like Carl Weathers likeness for Dillon). I'm sure it varies from each type of media, so the video games might be a little harder to get than say the comics. They've done it before though, and with the Predators (arguably) being their best selling line I'm sure we'll see the video games tapped eventually.
Some one had asked about the Dark Blade hunter from Concrete jungle on Twitter and Neca said it was a definite possibility.
On a side note I really think Neca should do a Predator "armory" pack like they did for the Colonial Marines.
Some new/retooled masks, armor bits, different plasma casters and mounts for them, reissued Renegade rifle and some other hand weapons like spears/swords.