Williams was losing playtime throughout this season, the last couple of games she is about the third guard in off the bench. Her decision making was suspect and had no outside shot, good on ball defense though.
Mills I thought would develop given more time. She has great foot speed, is excellent at breaking a press by herself, and was probably out best on-ball defender. She didn't have much of an outside shot but was at least willing to put one up now and then.
Not sure if declining playtime was a factor or if it was something else, but wish them both luck moving forward.