Awakening still had (relative) filler that it could have done without.
Sidequests and such. Amaranthine and Vigil's Keep runnin around. Zone filler stuff with minimal lore. These things generally fit the setting, I'm not complaining, but that 10-20 hours (or more if Nightmare or whatever) of Awakening could have easily been shaved down to 5-15 for a DLC format instead.
Whichhhh is probably how long Trespasser will end up being, depending on what content is available to you, and how completionist you are.
I see it as a possibility that Trespasser, when I play it, may still end up being 15+ hours. Yeah it won't be Awakening, but I'm also not going into this highly skeptical about it.