I don't think it's that he's too nice, it's that he doesn't have the brains to work out a problem in front of him. I don't think he's a truly well schooled boxer that has learnt to think about what is happening the right way. He's underperformed and lost now quite a few times, since he's been pushed beyond beating up tired journeymen. He's faced fighters with different styles and too many times he's failed when his robotic combinations, list of head/foot movement etc isn't enough to just blast somebody out. If it gets tactical or a new style is presented, he can't work it out. Perhaps his coaches are partly to blame but I think he is lacking in the fundamentals of being able to box well. Listen to him talk compared to other fighters and he had no real insight into anything and that shows in his fights.
And then we've had clowns talking about him "showing he can box" more after his recent fights, just because he doesn't knock somebody out or fights behind a predictable jab. Laughable.