If you had longer hands and/or better pinch grip you would be able to palm more worn out balls than you do now, THAT's all there is to it!
NO.
No matter how big my hand size would be, it would still come down to skin quality and "compatibility" of friction with the ball texture.
For example, I can palm some balls and a friend can't palm the balls I can palm, but he can palm some balls I can't palm. The difference? The ball texture. His palm skin has friction with some types of balls, my palm skin has friction with some OTHER types of balls.
Why do I say that palm size doesn't matter?
Because I had a period of time when I couldn't palm my size 5 ball. That's like me having a +4 inches of palm on a regular sized ball or something. It doesn't matter. If it slips, it slips. The end. In fact, if I try to squeeze it more it slips even harder.