Boston has better players than they're given credit for.
That being said, while it is obvious Terry does have some talent, shyt don't get real until you're being guarded by the teams best defender, and teams start throwing the kitchen sink at you in terms of defensive schemes.
Remember, Jeremy Lin was in beastmode until NBA defenses started to figure out his patterns.
If you think Terry Rozier is a replacement for Kyrie Irving, please never, ever apply for a GM job.
Give any NBA player enough minutes and touches - let alone a great system - and they'll give you numbers here and there. The great ones can do it once defenses start coming up with game plans to stop them.