Every collaboration they have tends to follow the same formula of relaxing and watching a film as they drink beers. It works with Culkin because he's a young guy who enjoys hanging out and partying. That won't work with Shatner. Shatner tends to like doing his own thing and he would just be annoyed by watching a bad film.

I have no doubt they'd ever have him on except for maybe a small passing skit as there's nothing they could really do with him. But again, that's not what Shatner does.

I can't think of any of the mains they could really have on that would help except maybe Brent Spiner.