I think people are too hard on Williams for the fumble problems. If people remember correctly some guy named Devontae Booker couldn’t hold on to the rock so he wasn’t the start when the season started in 2014.
Ball security is something that can easily be taught and fixed. You can’t teach speed. As for instinct it is really hard to say. Booker had an unique ability to find holes where there were none. Later in the season when William eventually took over there wasn’t much push from the O-line. Especially against BYU.
I’ll label Williams as a wait and see I guess, but I think he is the starter next year with McCormick coming in for change of pace & slot.