Ball obviously has potential. I like him better than Russell in the long run on a Lebron team. He plays much less selfishly than Russell. You already have enough ball hogs with Kuzma and Ingram. And Jason Kidd never had high percentages other than 3pt%, he was a better passer than Ball though.
Lakers had to trade him to get rid of Mozgov's $64m contract to have enough cap space for Lebron in 2018. It was a necessary trade. No one in their right mind would've taken Mozgov's contract without a young player with potential in return. Blame Mitch for signing that crazy Mozgov deal.