#1 Shinsuke Nakamura
Unlike Kevin Owens, Shinsuke Nakamura would need Paul Heyman the MOST on this list as his English isn't the best as of right now. Nakamura being a heel really helps the situation because Paul Heyman also does great being a guy that isn't very likable. Similar to the section about Samoa Joe, it would blow the roof off the place if Paul Heyman was seen helping a Smackdown Live superstar.
While the "God bless Nakamerica" and "No speak English" shticks were very entertaining, he would seem more like a heel if he would just speak Japanese and having Paul Heyman there, pretending to translate while trashing the audience would do for some pretty well thought out entertainment.
Also, doing the whole "I'm going to speak in my native language because I won't lower myself to your American filth" gimmick is always a good go-to for the foreign superstars. Cesaro (when he was Antonio) and Jinder Mahal to name a few.
Truth be told, Paul Heyman could be a perfect fit for anybody. He's just that good to be honest. Let's just hope WWE makes the right decision with picking who will be the next Paul Heyman guy/girl. Only time will tell and we can only wait and see.