If I were a professional boxer, and I had to choose one gift - it would be a titanium chin (actually a diamond chin). Because with such chin everything is easier. And the chances of success are very small with a pillow chin, regardless of devastating punches, speed, wizard defense, great technique and combos, heart...
Maybe stamina, fatigue makes cowards of us all after all. The ability to keep going for 12 rounds at the same pace is huge.
Probably a strong chin. I feel like you can work your way around just about every other weakness to some extent. No matter how good you are though, you’re going to get hit hard many times, and you need the whiskers to stand up to it.