The short answer is yes, in a vacuum I'd like Terry back and think letting him walk was a mistake, but he's been very good for Charlotte and don't think there's a deal that makes sense for both sides.
I bring up Rozier because they have Ball as the clear leader of their team and they have pretty terrible 5’s (Biyombo and Zeller).
Having Ball means you are ideally suited to having a shooter/scorer that can cover points as your other guard. They have two guys like that but Rozier is the better of the two. Its a nice fit for Charlotte, so I doubt they would want to change that, but they've made lots of mistakes over the years.
Rozier is a very good two way guard. He is head and shoulders better than Marcus Smart. It isn't close.
Marcus is a better defender, but only in ways we don't really need any more. We've got 3 other excellent defenders that can cover two's and three's. Rozier would actually be a better defender for the C's because he's able to stay in front of better point guards.
The difference in offense is huge. Marcus is a little better in passing in the half court, but Rozier is better at everything else.
Losing Rozier was one of Ainge's biggest fails.