Funny thing to me is in games where he's playing under control his hands look fine, it's when he's struggling he starts fumbling the ball imo. I'd say his hands are decent overall at the moment.
Ultimately, I'd tell you not to worry about it. Wiseman looks like the type of player that will be so obsessed with getting better that over time he will correct any weaknesses in his game. He's going to struggle at times this season but he'll learn from his mistakes eventually. I expect him to be a 20/10 player in two seasons, possibly less.