What makes a person naturally bad at boxing ?

T-Rex arms loma and frampton might have them and did ok

T-Rex arms

Your mom. Made me chuckle

Your mom.

If you had no sense of balance, it would be very difficult.

bad coordination, in combo with slow reflexes and u are goosed

Grit. How do they deal with adversity in the ring and out? How well do they take instruction? Arrogance often is counterproductive, because it sets a cap on performance. And if they're slow with hands, feet, or reflexes, that's an issue. Speed and strength and stamina can be trained to some extent, but there's more to it. Low fight IQ. There's some people who are just really dumb in the ring. Fear. Lots of people that wouldn't even dare to get in the ring, and others that will let fear keep them from doing what it takes to win.

No quick twitch muscles. Boxing is a twitch sport. U need that sudden explosion in ur punches or u wont land at the pro level