Yeah, I also hope at least some of the Straw Hats will go. The only major problem I had with the Paramount War was the fact that all of the other main characters were missing. As you guys said, Brook would be an especially good candidate. Not only because he seems to know about the Vinsmokes, but also just because he really needs more screentime. He's already the newest member and then got put on a bus in Dressrosa, so I feel like he needs the development even more than Sanji. (Not that I'm not glad Sanji's gonna get some focus. I'm definitely looking forward to it.) I, too, think it'd be cool if some of the samurai also came along, so we could see more of their powers.
Something I'd like to see that I don't think will happen? Some of the Heart Pirates going. I like Law a lot, and I'd be happy if he came along, but seeing how much focus he got in the two previous arcs, I'd totally understand if he took a break from the story and didn't come along, and I'd be okay with that. But all of the other Heart Pirates are disproportionately underused compared to him, especially considering that they're part of this alliance too, and I'd love to see them get more development. Still, I can't really think of an excuse for most of them to go along. Maybe Bepo, since Luffy's gonna need some other Mink besides Pekoms to come with him so he can get back to Zou afterwards (since Pekoms is probably gonna stay with Big Mom), but even that's a pretty big stretch (no pun intended). I see Carrot or maybe Wanda as much more likely candidates for that. Hopefully they at least get some development when the whole alliance goes to Wano.