The thing with Miz is that he's a super company man. His life's goal was always WWE and he's clearly happy there. So he'll probably never leave that bubble unless a really great opportunity comes along.
I always thought Sasha had major crossover appeal. She has the right look and a very "relateable" personality. Though, for Hollywood, she'll probably need some media training and definitely acting lessons.
Same with The New Day, particularly Woods and E. Being funny and appealing to kids can take you far.
Seth and Roman definitely have that appeal, looks-wise. Personality-wise, idk. Roman is kind of a much less personable Jason Momoa, and Seth is just a dork. But they could make that leap, and in Roman's case, WWE probably wants to make that happen to an extent.