Tommy for both, but greater is closer and a case can made for Griffith in greatness. In the "better" department, Griffith was a fighter who was very good at everything, yet not exceptional in any department. He was the ultimate jack of all trades. Well, actually thats false... he did have exceptional ring IQ and physical strength. Hearns was a generational type fighter. We haven't seen anything like him before or since. We'll probably never see a Tommy Hearns again, just like we'll never see a Duran, Tyson, Jones, Ali again. They're such rare, unique fighters. I would pick Tommy head-to-head over Emile at any weight.
I think Griffith was greater. He has a much deeper résumé, had great longevity and was a very dominant force at 160 as well 147. While I think Tommy has the edge in weight jumping, and possibly in their very, very best wins, I think Griffith's overall body of work was more impressive than Hearns'. Griffith also fought in a deeper era (IMO, although it's very close) and would be my pick for either the second or third greatest fighter of his era (after Ali, and arguably Ortiz), whereas Hearns would be fourth for his, IMO (below Duran, Hagler, Leonard, and Spinks).
Hearns was a more spectacular fighter than Griffith IMO, and is possibly more lethal to the very best fighters ever between welter and middleweight, but I think a wider scope of fighters could beat him due to his chin. Hearns' weaknesses are areas in which Emile excelled at. Chin, stamina, physical strength and ring IQ were Hearns' four biggest weaknesses, IMO. But yeah, I agree. Hearns was more impressive, but he was also more flawed.
I have no issue with your Griffith as a greater argument. On better, I just think Tommy is head-to-head harder to beat at 147-154. Outside of Leonard, the only clear favorite over Hearns from 147-154 is obviously Mr. Walker Smith. The same can't be said for Emile. It's true Griffith had less weaknesses than Hearns, but that can be said about a lot of guys.
