Lol Benicio Del Toro isn't a big name but I would've gladly taken him. He's an Oscar winner but he's very Adrien Brody-esque in terms of being a good, known actor but not a marquee name. He would've needed The Predator much like Adrien Brody needed Predators. Both B-list name actors. They're no Matt Damon or Hugh Jackman.
They're going for actors that aren't well known because that's all who'll take the project. Affleck, Cooper, Hardy, Bale, Del Toro, Franco and Ruffalo all rejected the movie.
But at least Covenant has a Fassbender. This doesn't have anybody, yet.