If Williams plays major minutes at PG this year then we are in bigger trouble. Rutherford will be fine. Just protect the ball and set other guys up. He won't be asked to do too much.
How can you come to the conclusion that "Rutherford will be fine" playing major minutes? He was the backup point guard on a 14-20 MAAC team who shot 24% from 3, had a 1:1 assist to turnover ratio, and who when it counted the most (in the semifinal and final of his conference tourney), played a total off only 22 minutes for said MAAC team in two games.
He's a practice body, and extreme depth, nothing more.
Williams is unproven, but was offered by LSU, Florida, West Virginia, and Texas. He is not a natural point guard, but as Marillac pointed out, highly skilled players like Simon can be utilized to be the backup point guard if need be. Especially when the other option is a guy who sucked eggs as the backup for a weak MAAC team.