Parsons will always be a step ahead of Morris. His approach to the game is like that of a veteran. Sometimes it is easy to forget that he is just a rookie. I still haven't seen evidence of Morris' shooting ability. What i have seen is Parsons never stop working since he left college. He is taking the Luis Scola approach to the game which has been proven to be successful.
Parsons is more of a complete player. He is already one of the better defenders on the team. He has shown the ability to make good passes and be more of a facilitator. He is also a good rebounder and his offense is improving (averaging 12 points per game this month). Plus, for anyone who followed him in college, he has been a really clutch player on both ends of the ball (hit 2 games winners at the buzzer his junior year). Morris does show potential, especially looking at how his brother has played in Phoenix, and he could turn into a good player. But there is a reason chandler is starting, and don't think that he has already reached his ceiling. As of right now I would prefer Parsons as a long term SF.
I think the cold hard truth may be that Morris is just an undersized power forward. What I'm seeing from Parsons on the defensive end is just blowing my mind. Parsons looks like he can guard anyone on the court. It looks like Morris has natural scoring ability near the basket so I wouldn't mind seeing him get some minutes as a backup PF.