Just a thought I had.. Nakamura is a great in ring performer and has all the charisma of the world. But his charisma is different than the usual WWE-style charisma. He's really bad at promos, mainly because he can't speak proper English, so he uses short sentences, that are, most of the time, effective. However Nakamura is definately an in ring artist, because he's a guy whose actions speak louder than words. And that's a style that fits NJPW, a company that doesn't have a weekly TV show, but relies mostly at the story that is being told inside the ring. And Nakamura is great at that. He can tell any story inside that ring.
So, why not pair him with someone that can tell a story outside of the ring? And that's of course Paul Heyman. The in-ring charisma of Nakamura combined with the out-of-the-ring charisma of Paul Heyman, would make an amazing spectacle. It's a great way to really cover Nakamura's shortcomings and highlight his strengths, which is his in-ring ability. Plus Heyman will give Nakamura the perfect backstory that both WWE and Nakamura have failed to give to the WWE Universe. Highlight his strong style, highlight his work in Japan, his MMA background. Video packages are not enough for this.
People want to see Ronda be paired with Heyman, but Ronda doesn't really need Paul. Ronda will learn to cut a promo, will learn how to express her emotions. She's there to learn. She's a ROOKIE. However Nakamura has already mastered all these qualities but he can't show us them, since he can't really speak the English language.
IMO, if there's one guy that needs Paul Heyman after Brock is gone, it's Shinsuke Nakamura. And with Brock out of the picture, Paul can view Nakamura as his #1 client, and not someone who is a filler (like Axel and Cesaro).