Irving has a tendency to hold the ball too long. He is getting better in that, but its still a tendency of his. Rozier offers a really good change-of-pace to Irving. He gets the ball moving. He drives and kicks.
On top of that, he provides some nasty disruptive defense.
I'm a believer in his game. I think his shooting percentages will come up a bit this year. I know its his 3rd year, but with the roster turnover, it seems like he has struggled to find a rhythm, especially with the early season injuries.
Our second unit with Morris, Smart, and Rozier has been decent. That unit can score, but has also had some droughts. There just aren't very many options out there that would be a significant upgrade offensively without sacrificing our defense.
By putting the emphasis on internal development (ala the Spurs), we open ourselves up for getting the right guys on good contracts. This is a transition of philosophy. I know Ainge has made a lot of trades, and he may make more in the future, but we may need to get used to the idea that any weaknesses we have will be addressed through internal develop. That's not fast and easy and flashy in the modern NBA Trade Machine era, but it is how to build a dynasty.