Hill isn't a great PG but he's clearly better than Mason. That's all we need to know. There's no reason Hill can't make gradual improvements in learning how to run the offense. Tony is still improving in this regard and he's one of the best PGs in the league.
Mason doesn't have the tools to be even a decent backup PG. Hill has quickness and a good handle. As he learns how to attack the basket better, he'll also learn how to pass out once he's gotten into the lane. At the least that's what I would hope.