He's not american and thats why he will never be the face of boxing. Americans control boxing, and the face of boxing will ever be an american fighter. The candidates can be Spence jr, Terence Crawford, Keith Thurman, or whatever next american boxer cames. Lomachenko, he's an eastern european person, and thats the most hated persons in America, he will never suceed in being popular in the Unitated States and thats where he fights. The real face of boxing right now is Joshua, and he fights always in Europe.
Also Mayweather damaged too much boxing to be recover in short time, it will have to take long time to heal before we talk about next "face" of boxing.