Tommy, albeit a wide points verdict, no KO most likely. Griffith, as has been said, fought exactly as hard as he needed to in a given fight. I infer that to mean that he in a way let the opponent dictate how the overall tenor of the fight was to play out, and he was skilled and flexible enough to adjust to whatever sort of fight might be required in a given instance. That's perhaps oversimplifying a bit, but I think there is more than a grain of truth there. In this way, Griffith was sort of a chameleon. I don't see anyone being able let Hearns dictate tempo and fight plan and get away with it. Leonard got there because he was even faster and had a fifth gear. Griffith had no such gear. Here, he's a step behind the whole fight, reaching and lunging here and there late as he gets more desperate but he doesn't have the tools to beat a Hearns.
Over 15 rounds i would take Griffith's all around game. Emile would have dug deep and gotten it into the later rounds. Hearns didn't take much punishment from Leonard yet he wilted.